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<title>Life Lexicon (H)</title>
<meta name="author" content="Stephen A. Silver">
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<center><A HREF="lex.htm">Introduction</A> | <A HREF="lex_bib.htm">Bibliography</A></center></center>
<hr>
<center>
<b>
<A HREF="lex_1.htm">1-9</A> |
<A HREF="lex_a.htm">A</A> |
<A HREF="lex_b.htm">B</A> |
<A HREF="lex_c.htm">C</A> |
<A HREF="lex_d.htm">D</A> |
<A HREF="lex_e.htm">E</A> |
<A HREF="lex_f.htm">F</A> |
<A HREF="lex_g.htm">G</A> |
<A HREF="lex_h.htm">H</A> |
<A HREF="lex_i.htm">I</A> |
<A HREF="lex_j.htm">J</A> |
<A HREF="lex_k.htm">K</A> |
<A HREF="lex_l.htm">L</A> |
<A HREF="lex_m.htm">M</A> |
<A HREF="lex_n.htm">N</A> |
<A HREF="lex_o.htm">O</A> |
<A HREF="lex_p.htm">P</A> |
<A HREF="lex_q.htm">Q</A> |
<A HREF="lex_r.htm">R</A> |
<A HREF="lex_s.htm">S</A> |
<A HREF="lex_t.htm">T</A> |
<A HREF="lex_u.htm">U</A> |
<A HREF="lex_v.htm">V</A> |
<A HREF="lex_w.htm">W</A> |
<A HREF="lex_x.htm">X</A> |
<A HREF="lex_y.htm">Y</A> |
<A href="lex_z.htm">Z</A></b>
</center>
<hr>
<p><a name=halfbakedknightship>:</a><b>half-baked knightship</b> ((6,3)<i>c</i>/2621440, p2621440) A <a href="lex_s.htm#selfsupporting">self-supporting</a>
<a href="lex_m.htm#macrospaceship">macro-spaceship</a> with adjustable period but fixed direction, based
on the <a href="#halfbakeryreaction">half-bakery reaction</a>. This was the first spaceship based on
this reaction, constructed in December 2014 by Adam P. Goucher. It
moves 6 cells horizontally and 3 cells vertically every 2621440+8<i>N</i>
ticks, depending on the relative spacing of the two halves. It is
one of the slowest known <a href="lex_k.htm#knightship">knightships</a>, and the first one that was
not a <a href="lex_g.htm#geminoid">Geminoid</a>. Chris Cain optimized the design a few days later to
create the <a href="lex_p.htm#parallelhbk">Parallel HBK</a>.
<p>The spaceship produces gliders from near-diagonal lines of
half-bakeries, which collide with each other at 180 degrees. These
collisions produce <a href="lex_m.htm#monochromaticsalvo">monochromatic salvos</a> that gradually build and
trigger <a href="lex_s.htm#seed">seeds</a>, which in turn eventually construct small
<a href="lex_s.htm#synchronized">synchronized</a> <a href="lex_s.htm#salvo">salvos</a> of gliders. These re-activate the lines of
half-bakeries, thus closing the cycle and moving the entire spaceship
obliquely by (6,3).
<p><a name=halfbakery>:</a><b>half bakery</b> = <a href="lex_b.htm#biloaf">bi-loaf</a>.
<p><a name=halfbakeryreaction>:</a><b>half-bakery reaction</b> The key reaction used in the
<a href="#halfbakedknightship">half-baked knightship</a> and <a href="lex_p.htm#parallelhbk">Parallel HBK</a>, where a half-bakery is
moved by (6,3) when a glider collides with it, and the glider
continues on a new lane. Ivan Fomichev noticed in May 2014 that
pairs of these reactions at the correct relative spacing can create
90-degree output gliders:
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:.............................O.$............................O..$............................OOO$...............................$...............................$...............................$...............................$...............................$...............................$...............................$....................OO.........$...................O..O........$...................O.O.........$.................OO.O..........$........O.......O..O...........$......OO........O.O............$.......OO........O.............$...............................$....OO.........................$...O..O........................$...O.O.........................$.OO.O..........................$O..O...........................$O.O............................$.O.............................$"
>.............................O.
............................O..
............................OOO
...............................
...............................
...............................
...............................
...............................
...............................
...............................
....................OO.........
...................O..O........
...................O.O.........
.................OO.O..........
........O.......O..O...........
......OO........O.O............
.......OO........O.............
...............................
....OO.........................
...O..O........................
...O.O.........................
.OO.O..........................
O..O...........................
O.O............................
.O.............................
</a></pre></td></tr></table></center>
<p><a name=halfdiagonal>:</a><b>half diagonal</b> A natural measurement of distance between parallel
glider lanes, or between <a href="lex_e.htm#elbow">elbow</a> locations in a <a href="lex_u.htm#universal">universal</a>
<a href="lex_c.htm#constructionarm">construction arm</a> <a href="lex_e.htm#elbowoperation">elbow operation</a> library. If two gliders are in
the same phase and exactly lined up vertically or horizontally, <i>N</i>
cells away from each other, then the two glider <a href="lex_l.htm#lane">lanes</a> are
considered to be <i>N</i> half diagonals (hd) apart. Gliders that are an
integer number of <a href="lex_f.htm#fulldiagonal">full diagonals</a> apart must be the same colour,
whereas integer <a href="#halfdiagonal">half diagonals</a> allow for both glider colours. See
<a href="lex_c.htm#colourofaglider">colour of a glider</a>, <a href="lex_l.htm#linearpropagator">linear propagator</a>.
<p><a name=halffleet>:</a><b>half fleet</b> = <a href="lex_s.htm#shiptie">ship-tie</a>
<p><a name=halfmax>:</a><b>Halfmax</b> A pattern that acts as a spacefiller in half of the Life
plane, found by Jason Summers in May 2005. It expands in three
directions at <i>c</i>/2, producing a triangular region that grows to fill
half the plane.
<p><a name=hammer>:</a><b>hammer</b> To hammer a <a href="lex_l.htm#lwss">LWSS</a>, <a href="lex_m.htm#mwss">MWSS</a> or <a href="#hwss">HWSS</a> is to smash things into
the rear end of it in order to transform it into a different type of
<a href="lex_s.htm#spaceship">spaceship</a>. A hammer is the object used to do the hammering. In the
following example by Dieter Leithner an LWSS is hammered by two more
LWSS to make it into an MWSS.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:O..O................$....O...OO..........$O...O..OOO.....OOOO.$.OOOO..OO.O....O...O$........OOO....O....$.........O......O..O$"
>O..O................
....O...OO..........
O...O..OOO.....OOOO.
.OOOO..OO.O....O...O
........OOO....O....
.........O......O..O
</a></pre></td></tr></table></center>
<p><a name=hammerhead>:</a><b>hammerhead</b> A certain front end for <a href="lex_c.htm#c2spaceship">c/2 spaceships</a>. The central
part of the hammerhead pattern is supported between two <a href="lex_m.htm#mwss">MWSS</a>. The
picture below shows a small example of a <a href="lex_s.htm#spaceship">spaceship</a> with a
hammerhead front end (the front 9 columns).
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:................O..$.OO...........O...O$OO.OOO.......O.....$.OOOOO.......O....O$..OOOOO.....O.OOOO.$......OOO.O.OO.....$......OOO....O.....$......OOO.OOO......$..........OO.......$..........OO.......$......OOO.OOO......$......OOO....O.....$......OOO.O.OO.....$..OOOOO.....O.OOOO.$.OOOOO.......O....O$OO.OOO.......O.....$.OO...........O...O$................O..$"
>................O..
.OO...........O...O
OO.OOO.......O.....
.OOOOO.......O....O
..OOOOO.....O.OOOO.
......OOO.O.OO.....
......OOO....O.....
......OOO.OOO......
..........OO.......
..........OO.......
......OOO.OOO......
......OOO....O.....
......OOO.O.OO.....
..OOOOO.....O.OOOO.
.OOOOO.......O....O
OO.OOO.......O.....
.OO...........O...O
................O..
</a></pre></td></tr></table></center>
<p><a name=hand>:</a><b>hand</b> Any object used as a <a href="lex_s.htm#slowsalvo">slow salvo</a> <a href="lex_t.htm#target">target</a> by a
<a href="lex_c.htm#constructionarm">construction arm</a>.
<p><a name=handshake>:</a><b>handshake</b> An old MIT name for <a href="lex_l.htm#lumpsofmuck">lumps of muck</a>, from the following
form (2 generations on from the <a href="lex_s.htm#stairstephexomino">stairstep hexomino</a>):
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:..OO.$.O.OO$OO.O.$.OO..$"
>..OO.
.O.OO
OO.O.
.OO..
</a></pre></td></tr></table></center>
<p><a name=harbor>:</a><b>harbor</b> (p5) Found by Dave Buckingham in September 1978. The name is
by Dean Hickerson.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:.....OO...OO.....$.....O.O.O.O.....$......O...O......$.................$.....OO...OO.....$OO..O.O...O.O..OO$O.O.OO.....OO.O.O$.O.............O.$.................$.O.............O.$O.O.OO.....OO.O.O$OO..O.O...O.O..OO$.....OO...OO.....$.................$......O...O......$.....O.O.O.O.....$.....OO...OO.....$"
>.....OO...OO.....
.....O.O.O.O.....
......O...O......
.................
.....OO...OO.....
OO..O.O...O.O..OO
O.O.OO.....OO.O.O
.O.............O.
.................
.O.............O.
O.O.OO.....OO.O.O
OO..O.O...O.O..OO
.....OO...OO.....
.................
......O...O......
.....O.O.O.O.....
.....OO...OO.....
</a></pre></td></tr></table></center>
<p><a name=harvester>:</a><b>harvester</b> (<i>c</i> p4 fuse) Found by David Poyner, this was the first
published example of a <a href="lex_f.htm#fuse">fuse</a>. The name refers to the fact that it
produces debris in the form of <a href="lex_b.htm#block">blocks</a> which contain the same number
of cells as the fuse has burnt up.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:................OO$...............O.O$..............O...$.............O....$............O.....$...........O......$..........O.......$.........O........$........O.........$.......O..........$......O...........$.....O............$OOOOO.............$OOOO..............$O.OO..............$"
>................OO
...............O.O
..............O...
.............O....
............O.....
...........O......
..........O.......
.........O........
........O.........
.......O..........
......O...........
.....O............
OOOOO.............
OOOO..............
O.OO..............
</a></pre></td></tr></table></center>
<p><a name=hashlife>:</a><b>hashlife</b> A Life algorithm by Bill Gosper that is designed to take
advantage of the considerable amount of repetitive behaviour in many
large patterns of interest. It provides a means of evolving
repetitive patterns millions (or even billions or trillions) of
generations further than normal Life algorithms can manage in a
reasonable amount of time.
<p>The hashlife algorithm is described by Gosper in his paper listed
in the bibliography at the end of this lexicon. Roughly speaking,
the idea is to store subpatterns in a hash table so that the results
of their <a href="lex_e.htm#evolution">evolution</a> do not need to be recomputed if they arise again
at some other place or time in the evolution of the full pattern.
This does, however, mean that complex patterns can require
substantial amounts of memory.
<p>Tomas Rokicki and Andrew Trevorrow implemented Hashlife into
<a href="lex_g.htm#golly">Golly</a> in 2005. See also <a href="lex_m.htm#macrocell">macrocell</a>.
<p><a name=hassle>:</a><b>hassle</b> See <a href="#hassler">hassler</a>.
<p><a name=hassler>:</a><b>hassler</b> An <a href="lex_o.htm#oscillator">oscillator</a> that works by hassling (repeatedly moving or
changing) some object. For some examples, see <a href="lex_j.htm#jolson">Jolson</a>,
<a href="lex_b.htm#bakersdozen">baker's dozen</a>, <a href="lex_t.htm#toadflipper">toad-flipper</a>, <a href="lex_t.htm#toadsucker">toad-sucker</a> and <a href="lex_t.htm#trafficcircle">traffic circle</a>.
Also see <a href="lex_p.htm#p24gun">p24 gun</a> for a good use of a <a href="lex_t.htm#trafficlight">traffic light</a> <a href="#hassler">hassler</a>.
<p><a name=hat>:</a><b>hat</b> (p1) Found in 1971. See also <a href="lex_t.htm#twinhat">twinhat</a> and <a href="lex_s.htm#sesquihat">sesquihat</a>.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:..O..$.O.O.$.O.O.$OO.OO$"
>..O..
.O.O.
.O.O.
OO.OO
</a></pre></td></tr></table></center>
<p><a name=hbk>:</a><b>HBK</b> = <a href="#halfbakedknightship">half-baked knightship</a>
<p><a name=hd>:</a><b>hd</b> Abbreviation for <a href="#halfdiagonal">half diagonal</a>. This metric is used primarily
for relative measurements of glider lanes, often in relation to
<a href="lex_s.htm#selfconstructing">self-constructing</a> circuitry; compare <a href="lex_g.htm#gn">Gn</a>.
<p><a name=heat>:</a><b>heat</b> For an <a href="lex_o.htm#oscillator">oscillator</a> or <a href="lex_s.htm#spaceship">spaceship</a>, the average number of cells
which change state in each generation. For example, the heat of a
<a href="lex_g.htm#glider">glider</a> is 4, because 2 cells are born and 2 die every generation.
<p>For a period <i>n</i> oscillator with an <i>r</i>-cell <a href="lex_r.htm#rotor">rotor</a> the heat is at
least 2<i>r</i>/<i>n</i> and no more than <i>r</i>(1-(<i>n</i> mod 2)/<i>n</i>). For <i>n</i>=2 and <i>n</i>=3 these
bounds are equal.
<p><a name=heavyweightemulator>:</a><b>heavyweight emulator</b> = <a href="#hwemulator">HW emulator</a>
<p><a name=heavyweightspaceship>:</a><b>heavyweight spaceship</b> = <a href="#hwss">HWSS</a>
<p><a name=heavyweightvolcano>:</a><b>heavyweight volcano</b> = <a href="#hwvolcano">HW volcano</a>
<p><a name=hebdarole>:</a><b>hebdarole</b> (p7) Found by Noam Elkies, November 1997. Compare
<a href="lex_f.htm#fumarole">fumarole</a>. The smaller version shown below was found soon after by
Alan Hensel using a component found by Dave Buckingham in June 1977.
The top ten rows can be stabilized by their mirror image (giving an
<a href="lex_i.htm#inductor">inductor</a>) and this was the original form found by Elkies.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:...........OO...........$....OO...O....O...OO....$.O..O..O.O....O.O..O..O.$O.O.O.OO.O....O.OO.O.O.O$.O..O..O.O.OO.O.O..O..O.$....OO....O..O....OO....$...........OO...........$.......O..O..O..O.......$......O.OO....OO.O......$.......O........O.......$........................$...OO..............OO...$...O..OOOO....OOOO..O...$....O.O.O.O..O.O.O.O....$...OO.O...OOOO...O.OO...$.......OO......OO.......$.........OO..OO.........$.........O..O.O.........$..........OO............$"
>...........OO...........
....OO...O....O...OO....
.O..O..O.O....O.O..O..O.
O.O.O.OO.O....O.OO.O.O.O
.O..O..O.O.OO.O.O..O..O.
....OO....O..O....OO....
...........OO...........
.......O..O..O..O.......
......O.OO....OO.O......
.......O........O.......
........................
...OO..............OO...
...O..OOOO....OOOO..O...
....O.O.O.O..O.O.O.O....
...OO.O...OOOO...O.OO...
.......OO......OO.......
.........OO..OO.........
.........O..O.O.........
..........OO............
</a></pre></td></tr></table></center>
<p><a name=hectic>:</a><b>hectic</b> (p30) Found by Robert Wainwright in September 1984.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:......................OO...............$......................OO...............$.......................................$.......................................$.......................................$.......................................$.......................................$.......................................$.......................................$.......................................$.......................................$.......................................$.........O..........OO...OO............$.......O.O............OOO..............$......O.O............O...O.............$OO...O..O.............O.O..............$OO....O.O..............O...............$.......O.O......O.O....................$.........O......OO.....................$.................O...O.................$.....................OO......O.........$....................O.O......O.O.......$...............O..............O.O....OO$..............O.O.............O..O...OO$.............O...O............O.O......$..............OOO............O.O.......$............OO...OO..........O.........$.......................................$.......................................$.......................................$.......................................$.......................................$.......................................$.......................................$.......................................$.......................................$.......................................$...............OO......................$...............OO......................$"
>......................OO...............
......................OO...............
.......................................
.......................................
.......................................
.......................................
.......................................
.......................................
.......................................
.......................................
.......................................
.......................................
.........O..........OO...OO............
.......O.O............OOO..............
......O.O............O...O.............
OO...O..O.............O.O..............
OO....O.O..............O...............
.......O.O......O.O....................
.........O......OO.....................
.................O...O.................
.....................OO......O.........
....................O.O......O.O.......
...............O..............O.O....OO
..............O.O.............O..O...OO
.............O...O............O.O......
..............OOO............O.O.......
............OO...OO..........O.........
.......................................
.......................................
.......................................
.......................................
.......................................
.......................................
.......................................
.......................................
.......................................
.......................................
...............OO......................
...............OO......................
</a></pre></td></tr></table></center>
<p><a name=heisenburpdevice>:</a><b>Heisenburp device</b> A pattern which can detect the passage of a
<a href="lex_g.htm#glider">glider</a> without affecting the glider's path or timing. The first
such device was constructed by David Bell in December 1992. The
term, coined by Bill Gosper, refers to the fact that Heisenberg's
Uncertainty Principle fails to apply in the Life universe. See also
<a href="lex_s.htm#stablepseudoheisenburp">stable pseudo-Heisenburp</a> and <a href="lex_n.htm#naturalheisenburp">natural Heisenburp</a>.
<p>The following is an example of the kind of reaction used at the
heart of a Heisenburp device. The glider at bottom right alters the
reaction of the other two gliders without itself being affected in
any way.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:O.....O....$.OO...O.O..$OO....OO...$...........$...........$...........$.........OO$........O.O$..........O$"
>O.....O....
.OO...O.O..
OO....OO...
...........
...........
...........
.........OO
........O.O
..........O
</a></pre></td></tr></table></center>
<p><a name=heisenburpeffect>:</a><b>Heisenburp effect</b> See <a href="#heisenburpdevice">Heisenburp device</a>.
<p><a name=helix>:</a><b>helix</b> A convoy of <a href="lex_s.htm#standardspaceship">standard spaceships</a> used in a <a href="lex_c.htm#caterpillar">Caterpillar</a> to
move some piece of debris at the speed of the Caterpillar. The
following diagram illustrates the idea. The leading edge of this
example helix, represented by the glider at the upper right in the
pattern below, moves at a speed of 65<i>c</i>/213, or slightly faster than
<i>c</i>/4.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:...............................O.............$.................O............OOO............$................OOO....OOO....O.OO...........$.........OOO....O.OO...O..O....OOO..OOO......$.........O..O....OOO...O.......OO...O........$.........O.......OO....O...O.........O.......$.........O...O.........O...O.................$OOO......O...O.........O.....................$O..O.....O..............O.O..................$O.........O.O................................$O............................................$.O.O.........................................$.............................................$.............................................$..........O..................................$.........OOO.................................$.........O.OO................................$..........OOO................................$..........OO.................................$.............................................$.............................................$...............OOO...........................$...............O..O....O.....OOO.............$...............O......OOO....O..O....O.......$...............O.....OO.O....O......OOO......$....OOO.........O.O..OOO.....O.....OO.O......$....O..O.............OOO......O.O..OOO.......$....O................OOO...........OOO.......$....O.................OO...........OOO.......$.....O.O............................OO.......$...........................................O.$..........................................OOO$.........................................OO.O$.........................................OOO.$..........................................OO.$.............................................$.............................................$.............................................$.............................................$.............................................$.............................................$.........................................O...$..............................OOO.......OOO..$................OOO.....O....O..O......OO.O..$..........O....O..O....OOO......O......OOO...$.........OOO......O....O.OO.....O......OOO...$.........O.OO.....O.....OOO..O.O........OO...$..........OOO..O.O......OOO..................$.O........OOO...........OOO..................$OOO.......OOO...........OO...................$O.OO......OO.................................$.OOO......................................O..$.OO......................................OOO.$........................................OO.O.$........................................OOO..$.........................................OO..$.........OOO.................................$........O..O.................................$...........O.................................$...........O.................................$........O.O..................................$"
>...............................O.............
.................O............OOO............
................OOO....OOO....O.OO...........
.........OOO....O.OO...O..O....OOO..OOO......
.........O..O....OOO...O.......OO...O........
.........O.......OO....O...O.........O.......
.........O...O.........O...O.................
OOO......O...O.........O.....................
O..O.....O..............O.O..................
O.........O.O................................
O............................................
.O.O.........................................
.............................................
.............................................
..........O..................................
.........OOO.................................
.........O.OO................................
..........OOO................................
..........OO.................................
.............................................
.............................................
...............OOO...........................
...............O..O....O.....OOO.............
...............O......OOO....O..O....O.......
...............O.....OO.O....O......OOO......
....OOO.........O.O..OOO.....O.....OO.O......
....O..O.............OOO......O.O..OOO.......
....O................OOO...........OOO.......
....O.................OO...........OOO.......
.....O.O............................OO.......
...........................................O.
..........................................OOO
.........................................OO.O
.........................................OOO.
..........................................OO.
.............................................
.............................................
.............................................
.............................................
.............................................
.............................................
.........................................O...
..............................OOO.......OOO..
................OOO.....O....O..O......OO.O..
..........O....O..O....OOO......O......OOO...
.........OOO......O....O.OO.....O......OOO...
.........O.OO.....O.....OOO..O.O........OO...
..........OOO..O.O......OOO..................
.O........OOO...........OOO..................
OOO.......OOO...........OO...................
O.OO......OO.................................
.OOO......................................O..
.OO......................................OOO.
........................................OO.O.
........................................OOO..
.........................................OO..
.........OOO.................................
........O..O.................................
...........O.................................
...........O.................................
........O.O..................................
</a></pre></td></tr></table></center>
<p>Adjustable-speed helices can produce a very wide range of spaceship
speeds; see <a href="lex_c.htm#caterloopillar">Caterloopillar</a>.
<p><a name=heptaplet>:</a><b>heptaplet</b> Any 7-cell <a href="lex_p.htm#polyplet">polyplet</a>.
<p><a name=heptapole>:</a><b>heptapole</b> (p2) The <a href="lex_b.htm#barberpole">barberpole</a> of length 7.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:OO........$O.O.......$..........$..O.O.....$..........$....O.O...$..........$......O.O.$.........O$........OO$"
>OO........
O.O.......
..........
..O.O.....
..........
....O.O...
..........
......O.O.
.........O
........OO
</a></pre></td></tr></table></center>
<p><a name=heptomino>:</a><b>heptomino</b> Any 7-cell <a href="lex_p.htm#polyomino">polyomino</a>. There are 108 such objects. Those
with names in common use are the <a href="lex_b.htm#bheptomino">B-heptomino</a>, the <a href="#herschel">Herschel</a> and
the <a href="lex_p.htm#piheptomino">pi-heptomino</a>.
<p><a name=herschel>:</a><b>Herschel</b> (stabilizes at time 128) The following pattern which occurs
at generation 20 of the <a href="lex_b.htm#bheptomino">B-heptomino</a>.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:O..$O.O$OOO$..O$"
>O..
O.O
OOO
..O
</a></pre></td></tr></table></center>
<p>The name is commonly ascribed to the Herschel heptomino's
similarity to a planetary symbol. William Herschel discovered Uranus
in 1781. However, in point of fact a Herschel bears no particular
resemblance to either of the symbols used for Uranus, but does
closely resemble the symbol for Saturn. So the appropriate name might
actually be "Huygens", but "Herschel" is now universally used by
tradition.
<p>Herschels are one of the most versatile types of <a href="lex_s.htm#signal">signal</a> in stable
circuitry. <a href="lex_r.htm#rpentomino">R-pentominoes</a> and <a href="lex_b.htm#bheptomino">B-heptominoes</a> naturally evolve into
Herschels, and <a href="lex_c.htm#converter">converters</a> have also been found that change
<a href="lex_p.htm#piheptomino">pi-heptominoes</a> and several other signal types into Herschels, and
vice versa. See <a href="lex_e.htm#elementaryconduit">elementary conduit</a>.
<p><a name=herschelcircuit>:</a><b>Herschel circuit</b> A series of <a href="#herschelconduit">Herschel conduits</a> or other components,
connected by placing them so that the output <a href="#herschel">Herschels</a> from early
conduits become the input Herschels for later conduits. Often the
initial component is a <a href="lex_c.htm#converter">converter</a> accepting some other signal type
as input - usually a glider, in which case a <a href="lex_s.htm#syringe">syringe</a> is most
commonly used. The <a href="lex_s.htm#silverreflector">Silver reflector</a> is a well-known early
<a href="lex_s.htm#spartan">Spartan</a> Herschel circuit from before the syringe was discovered,
where the initial converter is a <a href="lex_c.htm#callahangtoh">Callahan G-to-H</a>.
<p>Sometimes a direct connection between two conduits is not possible
due to unwanted gliders that destroy required <a href="lex_c.htm#catalyst">catalysts</a>, or wanted
gliders that are not able to escape. In this case, small "spacer"
conduits such as <a href="lex_f.htm#f116">F116</a>, <a href="lex_f.htm#f117">F117</a>, <a href="lex_f.htm#fx77">Fx77</a>, <a href="lex_r.htm#r64">R64</a>, <a href="lex_l.htm#l112">L112</a>, or <a href="lex_l.htm#l156">L156</a> can
be inserted between the other conduits to solve the problem.
<p>Some converter or <a href="lex_f.htm#factory">factory</a> conduits do not produce a Herschel as
output, instead generating other useful results such as gliders,
<a href="lex_b.htm#boat">boats</a> or <a href="lex_m.htm#mwss">MWSSes</a>. See <a href="#herscheltoglider">Herschel-to-glider</a>, <a href="lex_d.htm#demultiplexer">demultiplexer</a>, and
<a href="#htomwss">H-to-MWSS</a> respectively for examples of these. For those conduits
which do produce an unwanted Herschel, an <a href="lex_e.htm#eater">eater</a> such as <a href="lex_s.htm#sw2">SW-2</a> can
be added to delete it.
<p>If the first and last conduits of a chain connect to each other in
a loop then there is no need for a syringe to generate the first
Herschel, or an eater to consume the last one. The circuit becomes a
self-supporting <a href="#herschelloop">Herschel loop</a>. A loop is also formed by a
<a href="lex_s.htm#syringe">syringe</a> connected to a Herschel-to-glider converter, with the
glider reflected back to the syringe's input with glider reflectors
of the appropriate colour, usually <a href="lex_s.htm#snark">Snarks</a>. In either case, if the
loop has a surplus <a href="lex_g.htm#glider">glider</a> output, it becomes a <a href="lex_g.htm#gun">gun</a>; if no output
is available it is an <a href="lex_e.htm#emu">emu</a>.
<p><a name=herschelclimber>:</a><b>Herschel climber</b> Any <a href="lex_r.htm#reburnablefuse">reburnable fuse</a> reaction involving
<a href="#herschel">Herschels</a>. May refer specifically to the
<a href="lex_1.htm#a-235c79herschelclimber">(23,5)c/79 Herschel climber</a> used in the <a href="lex_w.htm#waterbear">waterbear</a>, or one of
several similar reactions with various velocities. See also
<a href="#herschelpairclimber">Herschel-pair climber</a>.
<p><a name=herschelcomponent>:</a><b>Herschel component</b> = <a href="#herschelconduit">Herschel conduit</a>
<p><a name=herschelconduit>:</a><b>Herschel conduit</b> A <a href="lex_c.htm#conduit">conduit</a> that moves a <a href="#herschel">Herschel</a> from one place
to another. See also <a href="#herschelloop">Herschel loop</a>.
<p>Well over a hundred simple stable Herschel conduits are currently
known. As of June 2018 the number is approximately 150, depending on
the precise definition of "simple" - e.g., fitting inside a 100x100
bounding box, and producing output in no more than 300 <a href="lex_t.htm#tick">ticks</a>. In
general a Herschel conduit can be called "simple" if its active
reaction does not return to a Herschel stage except at its output.
Compare <a href="lex_e.htm#elementaryconduit">elementary conduit</a>, <a href="lex_c.htm#compositeconduit">composite conduit</a>. A description of
common usage in complex circuitry, using <a href="lex_s.htm#syringe">syringes</a> and <a href="lex_s.htm#snark">Snarks</a> to
make compact connections, can be found in <a href="#herschelcircuit">Herschel circuit</a>.
<p>The original <a href="lex_u.htm#universal">universal</a> set consisted of sixteen stable Herschel
conduits, discovered between 1995 and 1998 by Dave Buckingham (DJB)
and Paul Callahan (PBC). These are shown in the following table. In
this table, the number in "name/steps" is the number of <a href="lex_t.htm#tick">ticks</a>
needed to produce an output Herschel from the input Herschel. "m"
tells how the Herschel is moved (R = turned right, L = turned left, B
= turned back, F = unturned, f = flipped), and "dx" and "dy" give the
displacement of the centre cell of the Herschel (assumed to start in
the orientation shown above).
<pre>
------------------------------------------
name/steps m dx dy discovery
------------------------------------------
<a href="lex_r.htm#r64">R64</a> R 11 9 DJB, Sep 1995
<a href="lex_f.htm#fx77">Fx77</a> Fflip 25 -8 DJB, Aug 1996
<a href="lex_l.htm#l112">L112</a> L 12 -33 DJB, Jul 1996
<a href="lex_f.htm#f116">F116</a> F 32 1 PBC, Feb 1997
<a href="lex_f.htm#f117">F117</a> F 40 -6 DJB, Jul 1996
<a href="lex_b.htm#bx125">Bx125</a> Bflip -9 -17 PBC, Nov 1998
<a href="lex_f.htm#fx119">Fx119</a> Fflip 20 14 DJB, Sep 1996
<a href="lex_f.htm#fx153">Fx153</a> Fflip 48 -4 PBC, Feb 1997
<a href="lex_l.htm#l156">L156</a> L 17 -41 DJB, Aug 1996
<a href="lex_f.htm#fx158">Fx158</a> Fflip 27 -5 DJB, Jul 1996
<a href="lex_f.htm#f166">F166</a> F 49 3 PBC, May 1997
<a href="lex_f.htm#fx176">Fx176</a> Fflip 45 0 PBC, Oct 1997
<a href="lex_r.htm#r190">R190</a> R 24 16 DJB, Jul 1996
<a href="lex_l.htm#lx200">Lx200</a> Lflip 17 -40 PBC, Jun 1997
<a href="lex_r.htm#rx202">Rx202</a> Rflip 7 32 DJB, May 1997
<a href="lex_b.htm#bx222">Bx222</a> Bflip -6 -16 PBC, Oct 1998
------------------------------------------
</pre>
<p>See also <a href="#herscheltransceiver">Herschel transceiver</a>.
<p><a name=herscheldescendant>:</a><b>Herschel descendant</b> A common active pattern occurring at generation
22 of a <a href="#herschel">Herschel</a>'s <a href="lex_e.htm#evolution">evolution</a>:
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:OO..$O.OO$...O$.O.O$.OO.$"
>OO..
O.OO
...O
.O.O
.OO.
</a></pre></td></tr></table></center>
There are other evolutionary paths leading to the same pattern,
including the modification of a <a href="lex_b.htm#bheptomino">B-heptomino</a> implied by generation
21 of a Herschel.
<p><a name=herschelgreatgrandparent>:</a><b>Herschel great-grandparent</b> A specific three-<a href="lex_t.htm#tick">tick</a> predecessor of a
<a href="#herschel">Herschel</a>, commonly seen in <a href="#herschelconduit">Herschel conduit</a> collections that
contain <a href="lex_d.htm#dependentconduit">dependent conduits</a>. In some situations it is helpful to
display the input reaction in this form instead of the standard
Herschel form.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:.OO....$OOO.OO.$.OO.OOO$OOO.OO.$OO.....$"
>.OO....
OOO.OO.
.OO.OOO
OOO.OO.
OO.....
</a></pre></td></tr></table></center>
<p>Dependent conduit inputs are catalysed by a <a href="lex_t.htm#transparent">transparent</a> block
before the Herschel's standard form can appear, and before the
Herschel's <a href="lex_f.htm#firstnaturalglider">first natural glider</a> is produced. This means that these
conduits will fail if an actual Herschel is placed in the "correct"
input location for a dependent conduit. Refer to <a href="lex_f.htm#f166">F166</a> or <a href="lex_l.htm#lx200">Lx200</a>
to see the correct relative placement of the standard transparent
block catalyst.
<p>Almost all known Herschel conduits produce a Herschel
great-grandparent near the end of their evolutionary sequence. In
the original <a href="lex_u.htm#universal">universal</a> set of Herschel conduits, <a href="lex_f.htm#fx158">Fx158</a> is the
only exception.
<p><a name=herschelloop>:</a><b>Herschel loop</b> A cyclic <a href="#herscheltrack">Herschel track</a>. Although no loop of length
less than 120 generations has been constructed it is possible to make
<a href="lex_o.htm#oscillator">oscillators</a> of smaller periods by putting more than one Herschel in
a higher-period track. In this way oscillators, and in most cases
<a href="lex_g.htm#gun">guns</a>, of all periods from 54 onwards can now be constructed
(although the p55 case is a bit strange, shooting itself with gliders
in order to stabilize itself). A mechanism for a period-52 loop was
found in April 2018, but it includes a stage where the signal is
carried by a triplet of <a href="lex_g.htm#glider">gliders</a> so it may not be considered to be a
pure Herschel loop. The missing period, 53, is a difficult case
simply because 53 is prime and so no small sparkers or reflectors are
available.
<p>See <a href="lex_s.htm#simkinglidergun">Simkin glider gun</a> and <a href="lex_p.htm#p256gun">p256 gun</a> for the smallest known
Herschel loops. See also <a href="lex_e.htm#emu">emu</a> and <a href="lex_o.htm#omniperiodic">omniperiodic</a>.
<p><a name=herschelpairclimber>:</a><b>Herschel-pair climber</b> Any <a href="lex_r.htm#reburnablefuse">reburnable fuse</a> reaction involving pairs
of <a href="#herschel">Herschels</a>. May refer specifically to the
<a href="lex_1.htm#a-31c240herschelpairclimber">31c/240 Herschel-pair climber</a> used in the <a href="lex_c.htm#centipede">Centipede</a>, or one of
several similar reactions with various velocities. See also
<a href="#herschelclimber">Herschel climber</a>.
<p><a name=herschelreceiver>:</a><b>Herschel receiver</b> Any <a href="lex_c.htm#circuit">circuit</a> that converts a <a href="lex_t.htm#tandemglider">tandem glider</a> into
a <a href="#herschel">Herschel</a> <a href="lex_s.htm#signal">signal</a>. The following diagram shows a pattern found
by Paul Callahan in 1996, as part of the first stable glider
<a href="lex_r.htm#reflector">reflector</a>. Used as a receiver, it converts two parallel input
gliders (with path separations of 2, 5, or 6) to an <a href="lex_r.htm#rpentomino">R-pentomino</a>.
The signal is then converted to a Herschel by one of several known
mechanisms, the first of which was found by Dave Buckingham way back
in 1972. The second is <a href="lex_e.htm#elementaryconduit">elementary conduit</a> <a href="lex_r.htm#rf48h">RF48H</a>, found by
Stephen Silver in October 1997. The receiver version shown below
uses Buckingham's R-to-Herschel converter, which is made up of
elementary conduit <a href="lex_r.htm#rf28b">RF28B</a> followed by <a href="lex_b.htm#bfx59h">BFx59H</a>.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:...............................................O.O$......................................OO.......OO.$......................................OO........O.$...OO.............................................$...O..............................................$....O.............................................$...OO.............................................$............OO....................................$...........O.O....................................$............O..............................O......$......................................OO...O.O....$.....................................O..O..OO.....$OO....................................OO..........$OO.............................OO.................$...............................OO.................$..................................................$..................................................$..................................................$..................................................$..................................................$..................................................$............................................OO....$............................................OO....$........................................OO........$........................................O.O.......$..........................................O.......$..........................................OO......$.............................OO...................$.............................OO...................$..................................................$..................................................$...........................OO.....................$...........................OO.....................$"
>...............................................O.O
......................................OO.......OO.
......................................OO........O.
...OO.............................................
...O..............................................
....O.............................................
...OO.............................................
............OO....................................
...........O.O....................................
............O..............................O......
......................................OO...O.O....
.....................................O..O..OO.....
OO....................................OO..........
OO.............................OO.................
...............................OO.................
..................................................
..................................................
..................................................
..................................................
..................................................
..................................................
............................................OO....
............................................OO....
........................................OO........
........................................O.O.......
..........................................O.......
..........................................OO......
.............................OO...................
.............................OO...................
..................................................
..................................................
...........................OO.....................
...........................OO.....................
</a></pre></td></tr></table></center>
<p><a name=herschelstopper>:</a><b>Herschel stopper</b> A method of cleanly suppressing a <a href="#herschel">Herschel</a> signal
with an <a href="lex_a.htm#asynchronous">asynchronous</a> <a href="lex_b.htm#boatbit">boat-bit</a>, discovered by Dean Hickerson.
Here a <a href="lex_g.htm#ghostherschel">ghost Herschel</a> marks the location of the output signal, in
cases where the boat-bit is not present. Other boat-bit locations
that allow for clean suppression of a Herschel are also known.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:....................................OO$.........................O..........O.$.........................OOO.........O$............................O.......OO$...........................OO.........$......................................$........O.............................$........OOO...........................$...........O..........................$..........OO...........OO...........O.$.......................OO.........OOO.$..................................O...$..................................O...$......................................$..........................O...........$..........................OO..........$.........O...............O.O..........$.........O.O..........................$.........OOO..........................$...........O.......................OO.$....................................O.$.................................OOO..$.................................O....$......................................$..OO..................................$...O..................................$OOO....................OO.............$O......................O..............$........................OOO...........$..........................O...........$"
>....................................OO
.........................O..........O.
.........................OOO.........O
............................O.......OO
...........................OO.........
......................................
........O.............................
........OOO...........................
...........O..........................
..........OO...........OO...........O.
.......................OO.........OOO.
..................................O...
..................................O...
......................................
..........................O...........
..........................OO..........
.........O...............O.O..........
.........O.O..........................
.........OOO..........................
...........O.......................OO.
....................................O.
.................................OOO..
.................................O....
......................................
..OO..................................
...O..................................
OOO....................OO.............
O......................O..............
........................OOO...........
..........................O...........
</a></pre></td></tr></table></center>
<p>This term is also sometimes used to refer to any mechanism that
cleanly suppresses a Herschel. These usually allow the Herschel's
<a href="lex_f.htm#firstnaturalglider">first natural glider</a> to escape, so they are more commonly
classified as <a href="lex_c.htm#converter">converters</a>. See <a href="lex_s.htm#sw2">SW-2</a>.
<p><a name=herscheltoglider>:</a><b>Herschel-to-glider</b> The largest category of <a href="lex_e.htm#elementaryconduit">elementary conduit</a>.
Gliders are very common and self-supporting, so it's much easier to
find these than any other type of output <a href="lex_s.htm#signal">signal</a>. A large
collection of these H-to-G <a href="lex_c.htm#converter">converters</a> has been compiled, with many
different output <a href="lex_l.htm#lane">lanes</a> and timings. These can be used to
synchronize multiple signals to produce <a href="lex_g.htm#gun">gun</a> patterns or complex
logic circuitry. See <a href="lex_n.htm#nw31t120">NW31T120</a> for an example.
<p><a name=herscheltrack>:</a><b>Herschel track</b> A <a href="lex_t.htm#track">track</a> for <a href="#herschel">Herschels</a>. An equivalent term is
<a href="#herschelcircuit">Herschel circuit</a>. See also <a href="lex_b.htm#btrack">B track</a>.
<p><a name=herscheltransceiver>:</a><b>Herschel transceiver</b> An adjustable <a href="#herschelconduit">Herschel conduit</a> made up of a
<a href="#herscheltransmitter">Herschel transmitter</a> and a <a href="#herschelreceiver">Herschel receiver</a>. The intermediate
stage consists of a <a href="lex_t.htm#tandemglider">tandem glider</a> - two <a href="lex_g.htm#glider">gliders</a> on parallel
<a href="lex_l.htm#lane">lanes</a> - so that the transmitter and receiver can be separated by
any required distance. The conduit may be <a href="lex_s.htm#stable">stable</a>, or may contain
low-period <a href="lex_o.htm#oscillator">oscillators</a>.
<p><a name=herscheltransmitter>:</a><b>Herschel transmitter</b> Any <a href="#herschel">Herschel</a>-to-two-<a href="lex_g.htm#glider">glider</a> <a href="lex_c.htm#converter">converter</a> that
produces a <a href="lex_t.htm#tandemglider">tandem glider</a> that can be used as input to a
<a href="#herschelreceiver">Herschel receiver</a>. If the gliders are far enough apart, and if one
of the gliders is used only for cleanup, then the transmitter is
<a href="lex_a.htm#ambidextrous">ambidextrous</a>: with a small modification to the receiver, a
suitably oriented mirror image of the receiver will also work.
<p>The following diagram shows a <a href="lex_s.htm#stable">stable</a> Herschel transmitter found
by Paul Callahan in May 1997:
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:......OO...........$.....O.O...........$...OOO.............$..O...O......O.....$..OO.OO......OOO...$.............O.O...$...............O...$...................$...................$OO.O...............$O.OO...............$...................$...................$...................$...............OO..$...............O...$................OOO$..................O$"
>......OO...........
.....O.O...........
...OOO.............
..O...O......O.....
..OO.OO......OOO...
.............O.O...
...............O...
...................
...................
OO.O...............
O.OO...............
...................
...................
...................
...............OO..
...............O...
................OOO
..................O
</a></pre></td></tr></table></center>
Examples of small reversible p6 and p7 transmitters are also known,
and more recently several alternate <a href="#herscheltransceiver">Herschel transceivers</a> have been
found with different lane spacing, e.g., 0, 2, 4, 6, and 13.
<p><a name=hertzoscillator>:</a><b>Hertz oscillator</b> (p8) Compare <a href="lex_n.htm#negentropy">negentropy</a>, and also <a href="lex_c.htm#cauldron">cauldron</a>.
Found by Conway's group in 1970.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:...OO.O....$...O.OO....$...........$....OOO....$...O.O.O.OO$...O...O.OO$OO.O...O...$OO.O...O...$....OOO....$...........$....OO.O...$....O.OO...$"
>...OO.O....
...O.OO....
...........
....OOO....
...O.O.O.OO
...O...O.OO
OO.O...O...
OO.O...O...
....OOO....
...........
....OO.O...
....O.OO...
</a></pre></td></tr></table></center>
<p><a name=hexadecimal>:</a><b>hexadecimal</b> = <a href="lex_b.htm#beehiveanddock">beehive and dock</a>
<p><a name=hexaplet>:</a><b>hexaplet</b> Any 6-cell <a href="lex_p.htm#polyplet">polyplet</a>.
<p><a name=hexapole>:</a><b>hexapole</b> (p2) The <a href="lex_b.htm#barberpole">barberpole</a> of length 6.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:OO.......$O.O......$.........$..O.O....$.........$....O.O..$.........$......O.O$.......OO$"
>OO.......
O.O......
.........
..O.O....
.........
....O.O..
.........
......O.O
.......OO
</a></pre></td></tr></table></center>
<p><a name=hexomino>:</a><b>hexomino</b> Any 6-cell <a href="lex_p.htm#polyomino">polyomino</a>. There are 35 such objects. For some
examples see <a href="lex_c.htm#century">century</a>, <a href="lex_s.htm#stairstephexomino">stairstep hexomino</a>, <a href="lex_t.htm#table">table</a>, <a href="lex_t.htm#toad">toad</a> and
<a href="lex_z.htm#zhexomino">Z-hexomino</a>.
<p><a name=hf>:</a><b>HF</b> = <a href="#honeyfarm">honey farm</a>
<p><a name=hfx58b>:</a><b>HFx58B</b> A common <a href="#herschel">Herschel</a> to <a href="lex_b.htm#bheptomino">B-heptomino</a> converter, used as the
first stage of <a href="lex_f.htm#f117">F117</a> and many other Herschel conduits. There are
two variants, both shown in the pattern below.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:..........O..............................O..........$..........OOO..........................OOO..........$.............O........................O.............$OO..........OO........................OO..........OO$.O................................................O.$.O.O............................................O.O.$..OO............................................OO..$.....................O........O.....................$.....................OO......OO.....................$......................OO....OO......................$......................O......O......................$.....................O........O.....................$....................................................$..O..............................................O..$..O.O..........................................O.O..$..OOO..........................................OOO..$....O...........OO.................OO..........O....$................O..................OO...............$.................OOO...................OO...........$...................O...................O............$........................................OOO.........$..........................................O.........$"
>..........O..............................O..........
..........OOO..........................OOO..........
.............O........................O.............
OO..........OO........................OO..........OO
.O................................................O.
.O.O............................................O.O.
..OO............................................OO..
.....................O........O.....................
.....................OO......OO.....................
......................OO....OO......................
......................O......O......................
.....................O........O.....................
....................................................
..O..............................................O..
..O.O..........................................O.O..
..OOO..........................................OOO..
....O...........OO.................OO..........O....
................O..................OO...............
.................OOO...................OO...........
...................O...................O............
........................................OOO.........
..........................................O.........
</a></pre></td></tr></table></center>
<p><a name=hheptomino>:</a><b>H-heptomino</b> Name given by Conway to the following <a href="#heptomino">heptomino</a>. After
one generation this is the same as the <a href="lex_i.htm#iheptomino">I-heptomino</a>.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:OO..$.O..$.OOO$..O.$"
>OO..
.O..
.OOO
..O.
</a></pre></td></tr></table></center>
<p><a name=highbandwidthtelegraph>:</a><b>high-bandwidth telegraph</b> (p960, p30 circuitry) A variant of the
<a href="lex_t.htm#telegraph">telegraph</a> constructed by Louis-François Handfield in February 2017,
using periodic components to achieve a transmission rate of one bit
per 192 ticks. The same ten signals are sent as in the original
<a href="lex_t.htm#telegraph">telegraph</a> and the <a href="lex_p.htm#p1telegraph">p1 telegraph</a>, but information is encoded more
efficiently in the timing of those signals. Specifically, the new
transmitter sends five bits every 960 ticks by adjusting the relative
timings inside each of the five mirror-image paired subunits of the
composite signal in the beehive-chain <a href="lex_l.htm#lightspeedwire">lightspeed wire</a> <a href="lex_f.htm#fuse">fuse</a>.
<p><a name=highclearance>:</a><b>high-clearance</b> See <a href="lex_c.htm#clearance">clearance</a>.
<p><a name=highwayrobber>:</a><b>highway robber</b> Any mechanism that can retrieve a signal from a
spaceship <a href="lex_l.htm#lane">lane</a> while allowing spaceships on nearby lanes to pass by
unaffected. In practice the spaceship is generally a glider. The
signal is removed from the lane, an output signal is generated
elsewhere, and the highway robber returns to its original state. A
competent highway robber does not affect gliders even on the lane
adjacent to the affected glider stream, except during its recovery
period.
<p>A perfect highway robber doesn't affect later gliders even in the
lane to which it is attached, even during its recovery period. Below
is a near-perfect highway robber "bait" that requires three
<a href="lex_s.htm#synchronized">synchronized</a> signals to rebuild (the <a href="#herschel">Herschel</a>, <a href="lex_b.htm#bheptomino">B-heptomino</a>, and
<a href="lex_g.htm#glider">glider</a>.) The glider at the top right passes by unharmed, but
another glider following on the same <a href="lex_l.htm#lane">lane</a> 200 ticks later will be
cleanly reflected to a new path, and another glider following that
one will also pass by unharmed. The only imperfection is a few ticks
at the very end of the reconstruction, as the beehive is being
rebuilt:
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:......................O...........O.........$......................OOO.......O.O.........$.........OO...OO.........O.......OO.........$.........OO...OO........OO..................$............................................$............................................$..OO........................................$...O........................................$...O.O......................................$....OO......................................$............................................$............................................$............................................$............................................$............................................$............................................$.......OO...................................$........O...................................$.....OOO....................................$.....O......................................$............................................$............................................$............................................$............................................$............................................$............................................$....................OO......................$....................OO......................$............OO..............................$.............O..............................$O.........OOO...............................$OOO.......O.................................$...O........................................$..OO........................................$............................................$............................................$............................................$............................................$...........O...........OO...............OO..$.........OOO..........O.O...............OO..$.........O.O............O...................$.........O.....................OO.O.......O.$...............................O.OO......OOO$........................................OO.O$............................................$.............................OO.............$.............................OO.............$.......................OO...................$.......................OO...................$............................................$............................................$.........................OO.................$..................OO.....OO.................$..................OO........................$"
>......................O...........O.........
......................OOO.......O.O.........
.........OO...OO.........O.......OO.........
.........OO...OO........OO..................
............................................
............................................
..OO........................................
...O........................................
...O.O......................................
....OO......................................
............................................
............................................
............................................
............................................
............................................
............................................
.......OO...................................
........O...................................
.....OOO....................................
.....O......................................
............................................
............................................
............................................
............................................
............................................
............................................
....................OO......................
....................OO......................
............OO..............................
.............O..............................
O.........OOO...............................
OOO.......O.................................
...O........................................
..OO........................................
............................................
............................................
............................................
............................................
...........O...........OO...............OO..
.........OOO..........O.O...............OO..
.........O.O............O...................
.........O.....................OO.O.......O.
...............................O.OO......OOO
........................................OO.O
............................................
.............................OO.............
.............................OO.............
.......................OO...................
.......................OO...................
............................................
............................................
.........................OO.................
..................OO.....OO.................
..................OO........................
</a></pre></td></tr></table></center>
<p><a name=hive>:</a><b>hive</b> = <a href="lex_b.htm#beehive">beehive</a>
<p><a name=hivenudger>:</a><b>hivenudger</b> (<i>c</i>/2 orthogonally, p4) A <a href="lex_s.htm#spaceship">spaceship</a> found by Hartmut
Holzwart in July 1992. (The name is due to Bill Gosper.) It
consists of a <a href="lex_p.htm#prebeehive">pre-beehive</a> escorted by four <a href="lex_l.htm#lwss">LWSS</a>. In fact any
LWSS can be replaced by a <a href="lex_m.htm#mwss">MWSS</a> or an <a href="#hwss">HWSS</a>, so that there are 45
different single-hive hivenudgers.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:OOOO.....O..O$O...O...O....$O.......O...O$.O..O...OOOO.$.............$.....OO......$.....OO......$.....OO......$.............$.O..O...OOOO.$O.......O...O$O...O...O....$OOOO.....O..O$"
>OOOO.....O..O
O...O...O....
O.......O...O
.O..O...OOOO.
.............
.....OO......
.....OO......
.....OO......
.............
.O..O...OOOO.
O.......O...O
O...O...O....
OOOO.....O..O
</a></pre></td></tr></table></center>
Wider versions can be made by stabilizing the front of the extended
"pre-beehive", as in the <a href="lex_l.htm#linepuffer">line puffer</a> shown below.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:.........O.O..................$........O..O..................$.......OO.....................$......O...O...................$.....OOO.O....................$..OO..........................$.O...OOOOO.......OOOO.....O..O$O...O............O...O...O....$O.....OO.........O.......O...O$OOO...OOOO........O..O...OOOO.$.O.......O....................$.OO...................OO......$.O.O..................OO......$.OO..OO.O........O.O..OO......$..O.OOO.O...O.OOOO.O..OO......$.........OO.O.OO..O...OO...OOO$....OOOOOO.OO...OOOO..OO...OOO$.....O....OOO......O..OO...OOO$......OO.....OO..OO...OO......$.......O..O.....OOOO..OO......$........O.O.OO.....O..OO......$......................OO......$..............................$..................O..O...OOOO.$.................O.......O...O$.................O...O...O....$.................OOOO.....O..O$"
>.........O.O..................
........O..O..................
.......OO.....................
......O...O...................
.....OOO.O....................
..OO..........................
.O...OOOOO.......OOOO.....O..O
O...O............O...O...O....
O.....OO.........O.......O...O
OOO...OOOO........O..O...OOOO.
.O.......O....................
.OO...................OO......
.O.O..................OO......
.OO..OO.O........O.O..OO......
..O.OOO.O...O.OOOO.O..OO......
.........OO.O.OO..O...OO...OOO
....OOOOOO.OO...OOOO..OO...OOO
.....O....OOO......O..OO...OOO
......OO.....OO..OO...OO......
.......O..O.....OOOO..OO......
........O.O.OO.....O..OO......
......................OO......
..............................
..................O..O...OOOO.
.................O.......O...O
.................O...O...O....
.................OOOO.....O..O
</a></pre></td></tr></table></center>
<p><a name=honeybit>:</a><b>honey bit</b> A block and pond <a href="lex_c.htm#constellation">constellation</a> used in the
<a href="lex_o.htm#otcametapixel">OTCA metapixel</a> by Brice Due in 2006, to store and retrieve a bit of
data - specifically, the presence or absence of a neighbor
<a href="lex_m.htm#metacell">metacell</a>. The "0" state of the honey bit memory unit is a simple
<a href="lex_b.htm#beehive">beehive</a>, which is also the source of the name.
<p>An input glider collides with the beehive to convert it into the
honey bit constellation, which can be thought of as a value of "1"
stored in the memory unit. A passing LWSS can then test for the
presence of the pond. If a collision occurs, the LWSS and the honey
bit constellation are mutually annihilated, leaving just the original
beehive. Below is the honeybit constellation with the two reactions
occurring in the opposite order - test, then reset.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:.O...............$..O..............$OOO..............$.................$............OOOO.$............O...O$............O....$.............O..O$.................$..........OO.....$.........O..O....$.........O..O....$..........OO.....$.................$.................$.........OO......$.........OO......$"
>.O...............
..O..............
OOO..............
.................
............OOOO.
............O...O
............O....
.............O..O
.................
..........OO.....
.........O..O....
.........O..O....
..........OO.....
.................
.................
.........OO......
.........OO......
</a></pre></td></tr></table></center>
If the pond is not present, the LWSS passes by the beehive without
affecting it. Thus a test input has an output for the "0" case, but
not for the "1" case. For an alternative memory-unit mechanism with
both "0" and "1" outputs, see <a href="lex_d.htm#demultiplexer">demultiplexer</a>.
<p>The honey bit is also an interesting <a href="lex_e.htm#eater">eater</a> for the <a href="#hwss">HWSS</a> as
shown below. An HWSS colliding with the pond happens to create the
exact same reset glider used in the above memory unit.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:..OO...........$O....O......OO.$......O....O..O$O.....O....O..O$.OOOOOO.....OO.$...............$...............$...........OO..$...........OO..$"
>..OO...........
O....O......OO.
......O....O..O
O.....O....O..O
.OOOOOO.....OO.
...............
...............
...........OO..
...........OO..
</a></pre></td></tr></table></center>
<p><a name=honeycomb>:</a><b>honeycomb</b> (p1)
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:..OO..$.O..O.$O.OO.O$.O..O.$..OO..$"
>..OO..
.O..O.
O.OO.O
.O..O.
..OO..
</a></pre></td></tr></table></center>
<p><a name=honeyfarm>:</a><b>honey farm</b> (p1) A common formation of four beehives.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:......O......$.....O.O.....$.....O.O.....$......O......$.............$.OO.......OO.$O..O.....O..O$.OO.......OO.$.............$......O......$.....O.O.....$.....O.O.....$......O......$"
>......O......
.....O.O.....
.....O.O.....
......O......
.............
.OO.......OO.
O..O.....O..O
.OO.......OO.
.............
......O......
.....O.O.....
.....O.O.....
......O......
</a></pre></td></tr></table></center>
<p><a name=hook>:</a><b>hook</b> Another term for a <a href="lex_b.htm#bookend">bookend</a>. It is also used for other
hook-shaped things, such as occur in the <a href="lex_e.htm#eater1">eater1</a> and the
<a href="#hookwithtail">hook with tail</a>, for example.
<p><a name=hookwithtail>:</a><b>hook with tail</b> (p1) For a long time this was the smallest
<a href="lex_s.htm#stilllife">still life</a> without a well-established name. It is now a vital
component of the smallest known <a href="#hwss">HWSS</a> <a href="lex_g.htm#gun">gun</a>, where it acts as a
<a href="lex_r.htm#rock">rock</a>.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:O.O..$OO.O.$...O.$...OO$"
>O.O..
OO.O.
...O.
...OO
</a></pre></td></tr></table></center>
<p><a name=houndstoothagar>:</a><b>houndstooth agar</b> The p2 <a href="lex_a.htm#agar">agar</a> that results from tiling the plane
with the following pattern.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:.OOO$.O..$..O.$OOO.$"
>.OOO
.O..
..O.
OOO.
</a></pre></td></tr></table></center>
<p><a name=house>:</a><b>house</b> The following <a href="lex_i.htm#inductioncoil">induction coil</a>. It is generation 3 of the
<a href="lex_p.htm#piheptomino">pi-heptomino</a>. See <a href="lex_s.htm#sparkcoil">spark coil</a> and <a href="lex_d.htm#deadsparkcoil">dead spark coil</a>.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:.OOO.$O...O$OO.OO$"
>.OOO.
O...O
OO.OO
</a></pre></td></tr></table></center>
<p><a name=htog>:</a><b>H-to-G</b> A <a href="#herscheltoglider">Herschel-to-glider</a> <a href="lex_c.htm#converter">converter</a>.
<p><a name=htomwss>:</a><b>H-to-MWSS</b> A <a href="lex_s.htm#spartan">Spartan</a> <a href="lex_c.htm#converter">converter</a> found by Tanner Jacobi in October
2015, which converts an input <a href="#herschel">Herschel</a> to a middleweight spaceship.
The key discovery was a very small but slightly <a href="lex_d.htm#dirty">dirty</a> H-to-MWSS
conduit, where a Herschel is catalyzed to produce an <a href="lex_m.htm#mwss">MWSS</a> but also
leaves behind a beehive. Prefixing two <a href="lex_r.htm#r64">R64</a> conduits to this
produces a <a href="lex_c.htm#composite">composite</a> converter that successfully deletes the
beehive in advance, using the input Herschel's
<a href="lex_f.htm#firstnaturalglider">first natural glider</a>.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:.............................OO................$.............................OO.....OO.........$....................................OO.........$...............................................$...............................................$...............OO.................OO...........$................O.................OO...........$................O.O.....................OO.....$.................OO.....................OO.....$...............................................$...............................................$...............................................$....................O..........................$....................O.O........................$....................OOO........................$......................O........................$...............................................$...............................................$...............................................$...............................................$...............................................$...............................................$...OO...........................OOO............$..O.O...........................O..............$...O...........................OO..............$...............................................$...............................................$...............................................$...............................................$...............................................$...............................................$.............................................OO$.O...........................................OO$O.O................OO.O........................$O.O................OO.OOO......................$.O......................O......................$........................O...............OO.....$........................................OO.....$....O.O.....................................OO.$.......O....................................OO.$...O...O.......................................$.......O.......................................$....O..O..............................OO.......$.....OOO..............................OO.......$"
>.............................OO................
.............................OO.....OO.........
....................................OO.........
...............................................
...............................................
...............OO.................OO...........
................O.................OO...........
................O.O.....................OO.....
.................OO.....................OO.....
...............................................
...............................................
...............................................
....................O..........................
....................O.O........................
....................OOO........................
......................O........................
...............................................
...............................................
...............................................
...............................................
...............................................
...............................................
...OO...........................OOO............
..O.O...........................O..............
...O...........................OO..............
...............................................
...............................................
...............................................
...............................................
...............................................
...............................................
.............................................OO
.O...........................................OO
O.O................OO.O........................
O.O................OO.OOO......................
.O......................O......................
........................O...............OO.....
........................................OO.....
....O.O.....................................OO.
.......O....................................OO.
...O...O.......................................
.......O.......................................
....O..O..............................OO.......
.....OOO..............................OO.......
</a></pre></td></tr></table></center>
There are many other ways to remove the beehive using a spare glider
or additional conduits, but they are generally less compact than
this.
<p><a name=hustler>:</a><b>hustler</b> (p3) Found by Robert Wainwright, June 1971.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:.....OO....$.....OO....$...........$...OOOO....$O.O....O...$OO.O...O...$...O...O.OO$...O....O.O$....OOOO...$...........$....OO.....$....OO.....$"
>.....OO....
.....OO....
...........
...OOOO....
O.O....O...
OO.O...O...
...O...O.OO
...O....O.O
....OOOO...
...........
....OO.....
....OO.....
</a></pre></td></tr></table></center>
<p><a name=hustlerii>:</a><b>hustler II</b> (p4)
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:....O...........$....OOO.........$.......O........$......O..OO.....$O.OO.O.OO..O....$OO.O.O.....O....$.....O....O.....$....O.....O.O.OO$....O..OO.O.OO.O$.....OO..O......$........O.......$.........OOO....$...........O....$"
>....O...........
....OOO.........
.......O........
......O..OO.....
O.OO.O.OO..O....
OO.O.O.....O....
.....O....O.....
....O.....O.O.OO
....O..OO.O.OO.O
.....OO..O......
........O.......
.........OOO....
...........O....
</a></pre></td></tr></table></center>
<p><a name=hwemulator>:</a><b>HW emulator</b> (p4) Found by Robert Wainwright in June 1980. See also
<a href="lex_e.htm#emulator">emulator</a>.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:.......OO.......$..OO.O....O.OO..$..O..........O..$...OO......OO...$OOO..OOOOOO..OOO$O..O........O..O$.OO..........OO.$"
>.......OO.......
..OO.O....O.OO..
..O..........O..
...OO......OO...
OOO..OOOOOO..OOO
O..O........O..O
.OO..........OO.
</a></pre></td></tr></table></center>
<p><a name=hwss>:</a><b>HWSS</b> (<i>c</i>/2 orthogonally, p4) A heavyweight spaceship, the fourth most
common <a href="lex_s.htm#spaceship">spaceship</a>. Found by Conway in 1970 by modifying a <a href="lex_l.htm#lwss">LWSS</a>.
See also <a href="lex_m.htm#mwss">MWSS</a>.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:...OO..$.O....O$O......$O.....O$OOOOOO.$"
>...OO..
.O....O
O......
O.....O
OOOOOO.
</a></pre></td></tr></table></center>
<p>The HWSS possesses both a <a href="lex_t.htm#tailspark">tail spark</a> and a <a href="lex_d.htm#domino">domino</a> <a href="lex_b.htm#bellyspark">belly spark</a>
which can easily perturb other objects as it passes by. The
spaceship can also perturb some objects in additional ways. For
examples, see <a href="lex_p.htm#puffer">puffer</a> and <a href="lex_g.htm#gliderturner">glider turner</a>.
<p>Dave Buckingham found that the HWSS can be synthesized using three
gliders as shown below:
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:........O.O$........OO.$.........O.$...........$OOO........$..O........$.O...OOO...$.......O...$......O....$"
>........O.O
........OO.
.........O.
...........
OOO........
..O........
.O...OOO...
.......O...
......O....
</a></pre></td></tr></table></center>
<p><a name=hwssemulator>:</a><b>HWSS emulator</b> = <a href="#hwemulator">HW emulator</a>
<p><a name=hwvolcano>:</a><b>HW volcano</b> (p5) A p5 <a href="lex_d.htm#domino">domino</a> <a href="lex_s.htm#sparker">sparker</a>, found by Dean Hickerson in
February 1995.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:.........O..........................$........O.O.........................$......OOO.O.........................$.....O....OO.O......................$.....O.OO...OO......OO..............$....OO.O.OO.........O.O.............$.........O.OOOOO......O..O.OO.......$..O.OO.OO.O.....O....OO.O.OO.O......$.....OO.....OOOO........O....O......$O...O.O..O...O.O....OO.O.OOOO.OO....$O...O.O..OO.O.OO.OO....O.O....O.O...$.....OO...OOO.OO.O.OOO.O..OOO...O...$..O.OO.OO.OO.............O.O..O.O.OO$...........O......O.O.O.O..OO.O.O.O.$....OO.O.O.OO......OO.O.O.O...O.O.O.$.....O.OO.O..O.......O.OO..OOOO.OO..$.....O....O.O........O...OO.........$....OO....OO........OO...O..O.......$...........................OO.......$"
>.........O..........................
........O.O.........................
......OOO.O.........................
.....O....OO.O......................
.....O.OO...OO......OO..............
....OO.O.OO.........O.O.............
.........O.OOOOO......O..O.OO.......
..O.OO.OO.O.....O....OO.O.OO.O......
.....OO.....OOOO........O....O......
O...O.O..O...O.O....OO.O.OOOO.OO....
O...O.O..OO.O.OO.OO....O.O....O.O...
.....OO...OOO.OO.O.OOO.O..OOO...O...
..O.OO.OO.OO.............O.O..O.O.OO
...........O......O.O.O.O..OO.O.O.O.
....OO.O.O.OO......OO.O.O.O...O.O.O.
.....O.OO.O..O.......O.OO..OOOO.OO..
.....O....O.O........O...OO.........
....OO....OO........OO...O..O.......
...........................OO.......
</a></pre></td></tr></table></center>
At least four progressively smaller forms of this sparker have been
found, including a 25-cell-wide version found by David Eppstein in
2003, and a vertically narrower 28-cell-wide version by Karel Suhajda
in 2004. Scot Ellison's 17-cell-wide version is shown in the
<a href="lex_z.htm#zweiback">zweiback</a> entry.
<p><a name=hybridgreyship>:</a><b>hybrid grey ship</b> A <a href="lex_g.htm#greyship">grey ship</a> containing more than one type of
region of density 1/2, usually a combination of a
<a href="lex_w.htm#withthegraingreyship">with-the-grain grey ship</a> and an <a href="lex_a.htm#againstthegraingreyship">against-the-grain grey ship</a>.
<hr>
<center>
<b>
<a href="lex_1.htm">1-9</a> |
<a href="lex_a.htm">A</a> |
<a href="lex_b.htm">B</a> |
<a href="lex_c.htm">C</a> |
<a href="lex_d.htm">D</a> |
<a href="lex_e.htm">E</a> |
<a href="lex_f.htm">F</a> |
<a href="lex_g.htm">G</a> |
<a href="lex_h.htm">H</a> |
<a href="lex_i.htm">I</a> |
<a href="lex_j.htm">J</a> |
<a href="lex_k.htm">K</a> |
<a href="lex_l.htm">L</a> |
<a href="lex_m.htm">M</a> |
<a href="lex_n.htm">N</a> |
<a href="lex_o.htm">O</a> |
<a href="lex_p.htm">P</a> |
<a href="lex_q.htm">Q</a> |
<a href="lex_r.htm">R</a> |
<a href="lex_s.htm">S</a> |
<a href="lex_t.htm">T</a> |
<a href="lex_u.htm">U</a> |
<a href="lex_v.htm">V</a> |
<a href="lex_w.htm">W</a> |
<a href="lex_x.htm">X</a> |
<a href="lex_y.htm">Y</a> |
<A href="lex_z.htm">Z</A></b>
</center>
<hr>
</body>
|
