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|
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html lang="en">
<head>
<title>Life Lexicon (D)</title>
<meta name="author" content="Stephen A. Silver">
<meta name="description" content="Part of Stephen Silver's Life Lexicon.">
<meta http-equiv="Content-Type" content="text/html; charset=us-ascii">
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<link rel="begin" type="text/html" href="lex.htm" title="Life Lexicon">
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<body bgcolor="#FFFFCE">
<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=dart>:</a><b>dart</b> (<i>c</i>/3 orthogonally, p3) Found by David Bell, May 1992. A
25-glider recipe for the dart was found in December 2014 by Martin
Grant and Chris Cain, making it the first glider-constructible <i>c</i>/3
spaceship.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:.......O.......$......O.O......$.....O...O.....$......OOO......$...............$....OO...OO....$..O...O.O...O..$.OO...O.O...OO.$O.....O.O.....O$.O.OO.O.O.OO.O.$"
>.......O.......
......O.O......
.....O...O.....
......OOO......
...............
....OO...OO....
..O...O.O...O..
.OO...O.O...OO.
O.....O.O.....O
.O.OO.O.O.OO.O.
</a></pre></td></tr></table></center>
<p><a name=deadsparkcoil>:</a><b>dead spark coil</b> (p1) Compare <a href="lex_s.htm#sparkcoil">spark coil</a>.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:OO...OO$O.O.O.O$..O.O..$O.O.O.O$OO...OO$"
>OO...OO
O.O.O.O
..O.O..
O.O.O.O
OO...OO
</a></pre></td></tr></table></center>
<p><a name=debris>:</a><b>debris</b> = <a href="lex_a.htm#ash">ash</a>.
<p><a name=debruijndiagram>:</a><b>de Bruijn diagram</b> = <a href="#debruijngraph">de Bruijn graph</a>
<p><a name=debruijngraph>:</a><b>de Bruijn graph</b> As applied to Life, a de Bruijn graph is a graph
showing which pieces can be linked to which other pieces to form a
valid part of a Life pattern of a particular kind.
<p>For example, if we are interested in <a href="lex_s.htm#stilllife">still lifes</a>, then we could
consider 2x3 rectangular pieces and the de Bruijn graph would show
which pairs of these can be overlapped to form 3x3 squares in which
the centre cell remains unchanged in the next generation.
<p>David Eppstein's <a href="lex_s.htm#searchprogram">search program</a> <a href="lex_g.htm#gfind">gfind</a> is based on de Bruijn
graphs.
<p><a name=deepcell>:</a><b>Deep Cell</b> A pattern by Jared James Prince, based on David Bell's
<a href="lex_u.htm#unitlifecell">unit Life cell</a>, in which each unit cell simulates two Life cells,
in such a way that a Life universe filled with Deep Cells simulates
two independent Life universes running in parallel.
<p>In fact, a Life universe filled with Deep Cells can simulate
infinitely many Life universes, as follows. Let <i>P</i><sub>1</sub>, <i>P</i><sub>2</sub>, <i>P</i><sub>3</sub>, ...
be a sequence of Life patterns. Set the Deep Cells to run a
simulation of <i>P</i><sub>1</sub> in parallel with a simulation of a universe filled
with Deep Cells, with these simulated Deep Cells running a simulation
of <i>P</i><sub>2</sub> in parallel with another simulation of a universe filled with
Deep Cells, with these doubly simulated Deep Cells simulating <i>P</i><sub>3</sub> in
parallel with yet another universe of Deep Cells, and so on.
<p>Deep Cell is available from <a href="http://psychoticdeath.com/life.htm">http://psychoticdeath.com/life.htm</a>.
<p><a name=demonoid>:</a><b>Demonoid</b> The first <a href="lex_s.htm#selfconstructing">self-constructing</a> diagonal spaceship. A 0<a href="lex_h.htm#hd">hd</a>
Demonoid was completed by Chris Cain in December 2015, shortly after
a much larger 10hd version was constructed the previous month in
collaboration with Dave Greene. The 0hd spaceship fits in a bounding
box about 55,000 cells square, and displaces itself by 65 cells
diagonally every 438,852 generations.
<p>The first 0hd Demonoid was fired by a <a href="lex_g.htm#gun">gun</a>. No spaceship gun
pattern had previously been completed before the first appearance of
the actual spaceship.
<p>In June 2017 Dave Greene completed a much simpler <a href="lex_s.htm#singlechannel">single-channel</a>
Demonoid using a temporary <a href="lex_l.htm#losslesselbow">lossless elbow</a>, which displaces itself
79 cells diagonally every 1,183,842 ticks. This was an improvement
in terms of design complexity, but not in terms of speed, population,
or bounding box. However, all of these could be further optimized.
A smaller Hashlife-friendly single-channel Demonoid design was
completed in 2018.
<p><a name=demultiplexer>:</a><b>demultiplexer</b> A simple <a href="lex_h.htm#herschel">Herschel</a> <a href="lex_c.htm#circuit">circuit</a> consisting of three
<a href="lex_e.htm#eater1">eater1s</a>, found by Brice Due in August 2006. An input Herschel
places a boat in a location accessible to an input glider. If the
boat is present, a <a href="lex_o.htm#onetime">one-time</a> <a href="lex_t.htm#turner">turner</a> reaction occurs and the glider
is turned 90 degrees onto a new lane.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:...........................O.....$........OO.................O.O...$.........O.................OO....$.........O.O.....................$..........OO.....................$.......................OO........$.......................O.O.......$........................O........$.................................$.................................$.............................OO..$..........O..................O.O.$..........O.O..................O.$..........OOO............OO....OO$............O............O.O.....$...........................O.....$...........................OO....$.................................$.................................$..OO.............................$.O.O.............................$.O...............................$OO...............................$"
>...........................O.....
........OO.................O.O...
.........O.................OO....
.........O.O.....................
..........OO.....................
.......................OO........
.......................O.O.......
........................O........
.................................
.................................
.............................OO..
..........O..................O.O.
..........O.O..................O.
..........OOO............OO....OO
............O............O.O.....
...........................O.....
...........................OO....
.................................
.................................
..OO.............................
.O.O.............................
.O...............................
OO...............................
</a></pre></td></tr></table></center>
If the Herschel and boat are removed from the above pattern, the
glider passes cleanly through the circuit. It can be used as the "0"
output of a one-bit <a href="lex_m.htm#memorycell">memory cell</a>, where the 90-degree output would
be the "1" output. This was the method used to store presence or
absence of neighbor <a href="lex_m.htm#metacell">metacells</a> in the <a href="lex_p.htm#p1megacell">p1 megacell</a>.
<p><a name=demuxer>:</a><b>demuxer</b> = <a href="#demultiplexer">demultiplexer</a>
<p><a name=density>:</a><b>density</b> The density of a pattern is the limit of the proportion of
live cells in a (2<i>n</i>+1)x(2<i>n</i>+1) square centred on a particular cell as
<i>n</i> tends to infinity, when this limit exists. (Note that it does not
make any difference what cell is chosen as the centre cell. Also
note that if the pattern is finite then the density is zero.) There
are other definitions of density, but this one will do here.
<p>In 1994 Noam Elkies proved that the maximum density of a stable
pattern is 1/2, which had been the conjectured value. See the paper
listed in the bibliography. Marcus Moore provided a simpler proof in
1995, and in fact proves that a <a href="lex_s.htm#stilllife">still life</a> with an <i>m</i> x <i>n</i>
<a href="lex_b.htm#boundingbox">bounding box</a> has at most (<i>mn</i>+<i>m</i>+<i>n</i>)/2 cells.
<p>But what is the maximum average density of an oscillating pattern?
The answer is conjectured to be 1/2 again, but this remains unproved.
The best upper bound so far obtained is 8/13 (Hartmut Holzwart,
September 1992).
<p>The maximum possible density for a <a href="lex_p.htm#phase">phase</a> of an oscillating
pattern is also unknown. An example with a density of 3/4 is known
(see <a href="lex_a.htm#agar">agar</a>), but densities arbitrarily close to 1 may perhaps be
possible.
<p><a name=dependentconduit>:</a><b>dependent conduit</b> A <a href="lex_h.htm#herschelconduit">Herschel conduit</a> in which the input <a href="lex_h.htm#herschel">Herschel</a>
interacts with catalysts in the first few ticks. The standard
interaction actually starts at T=-3, before the Herschel is
completely formed. Compare <a href="lex_i.htm#independentconduit">independent conduit</a>. The Herschel is
prevented from emitting its <a href="lex_f.htm#firstnaturalglider">first natural glider</a>. This is useful
in cases where the previous conduit cannot survive a first natural
glider emitted from its output Herschel.
<p>This term is somewhat confusing, since it is actually the previous
conduit that depends on the dependent conduit to suppress the
problematic glider. Dependent conduits such as the <a href="lex_f.htm#f166">F166</a> and
<a href="lex_l.htm#lx200">Lx200</a> do not actually depend on anything. They can be freely
connected to any other conduits that fit, as long as the output
Herschel evolves from its standard great-grandparent. As of this
writing, the <a href="lex_f.htm#fx158">Fx158</a> is the only known case where a conduit's output
Herschel has an alternate great-grandparent, which is incompatible
with dependent conduits' initial transparent block.
<p><a name=destructiveread>:</a><b>destructive read</b> The most common type of test reaction in
<a href="lex_m.htm#memorycell">memory cell</a> circuitry. Information is stored in a memory cell by
placing objects in known positions, or by changing the state of a
stable or periodic <a href="lex_t.htm#togglecircuit">toggle circuit</a>. A destructive-read test
consists of sending one or more <a href="lex_s.htm#signal">signals</a> to the memory cell. A
distinct output signal is produced for each possible state of the
memory cell, which is reset to a known "zero" or "rest" state. See
for example <a href="lex_b.htm#boatbit">boat-bit</a>, <a href="lex_k.htm#keeper">keeper</a>, and <a href="#demultiplexer">demultiplexer</a>.
<p>To permanently store information in a destructive-read memory cell,
the output signal(s) must be used, in part, to send appropriate
signals back to the memory cell to restore its state to its previous
value. With output looped back to input, this larger composite
circuit then effectively becomes a <a href="lex_n.htm#nondestructiveread">non-destructive read</a> memory
cell.
<p><a name=destructorarm>:</a><b>destructor arm</b> A dedicated <a href="lex_c.htm#constructionarm">construction arm</a> in the <a href="lex_g.htm#gemini">Gemini</a>
spaceship, used only for removing previously active <a href="lex_c.htm#circuit">circuitry</a> once
it is no longer needed. More generally, any circuitry in a
self-constructing pattern dedicated exclusively to cleanup.
<p><a name=dheptomino>:</a><b>D-heptomino</b> = <a href="lex_h.htm#herschel">Herschel</a>
<p><a name=diamond>:</a><b>diamond</b> = <a href="lex_t.htm#tub">tub</a>
<p><a name=diamondring>:</a><b>diamond ring</b> (p3) Found by Dave Buckingham in 1972.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:......O......$.....O.O.....$....O.O.O....$....O...O....$..OO..O..OO..$.O....O....O.$O.O.OO.OO.O.O$.O....O....O.$..OO..O..OO..$....O...O....$....O.O.O....$.....O.O.....$......O......$"
>......O......
.....O.O.....
....O.O.O....
....O...O....
..OO..O..OO..
.O....O....O.
O.O.OO.OO.O.O
.O....O....O.
..OO..O..OO..
....O...O....
....O.O.O....
.....O.O.....
......O......
</a></pre></td></tr></table></center>
<p><a name=diehard>:</a><b>diehard</b> Any pattern that vanishes, but only after a long time. The
following example vanishes in 130 generations, which is probably the
limit for patterns of 7 or fewer cells. Note that there is no limit
for higher numbers of cells. E.g., for 8 cells we could have a
glider heading towards an arbitrarily distant blinker.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:......O.$OO......$.O...OOO$"
>......O.
OO......
.O...OOO
</a></pre></td></tr></table></center>
<p><a name=dinnertable>:</a><b>dinner table</b> (p12) Found by Robert Wainwright in 1972.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:.O...........$.OOO.......OO$....O......O.$...OO....O.O.$.........OO..$.............$.....OOO.....$.....OOO.....$..OO.........$.O.O....OO...$.O......O....$OO.......OOO.$...........O.$"
>.O...........
.OOO.......OO
....O......O.
...OO....O.O.
.........OO..
.............
.....OOO.....
.....OOO.....
..OO.........
.O.O....OO...
.O......O....
OO.......OOO.
...........O.
</a></pre></td></tr></table></center>
<p><a name=dirty>:</a><b>dirty</b> Opposite of <a href="lex_c.htm#clean">clean</a>. A reaction which produces a large amount
of complicated junk which is difficult to control or use is said to
be dirty. Many basic <a href="lex_p.htm#pufferengine">puffer engines</a> are dirty and need to be
<a href="lex_t.htm#tame">tamed</a> by accompanying <a href="lex_s.htm#spaceship">spaceships</a> in order to produce clean
output. Similarly, a dirty <a href="lex_c.htm#conduit">conduit</a> is one that does not recover
perfectly after the passage of a <a href="lex_s.htm#signal">signal</a>; one or more extra <a href="lex_a.htm#ash">ash</a>
objects are left behind (or more rarely a <a href="lex_c.htm#catalyst">catalyst</a> is damaged) and
additional signals must be used to clean up the circuit before it can
be re-used.
<p><a name=diuresis>:</a><b>diuresis</b> (p90) Found by David Eppstein in October 1998. His original
stabilization used <a href="lex_p.htm#pentadecathlon">pentadecathlons</a>. The stabilization with
complicated <a href="lex_s.htm#stilllife">still lifes</a> shown here (in two slightly different
forms) was found by Dean Hickerson the following day. The name is
due to Bill Gosper (see <a href="lex_k.htm#kidney">kidney</a>).
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:.....OO................OO....$......O................O.....$......O.O............O.O.....$.......OO............OO......$.............................$....OO..................OO...$....O.O..........OO....O.O...$.....O..........O.O.....O....$..O.............OO.........O.$..OOOOOO........O.....OOOOOO.$.......O..............O......$....OO..................OO...$....O....................O...$.....O..................O....$..OOO..O..............O..OOO.$..O..OOO........O.....OOO...O$...O............OO.......OOO.$....OO..........O.O.....O....$......O..........OO....O..OO.$....OO..................OO.O.$.O..O....................O...$O.O.O..OO............OO..O...$.O..O.O.O............O.O.OO..$....O.O................O..O..$.....OO................OO....$"
>.....OO................OO....
......O................O.....
......O.O............O.O.....
.......OO............OO......
.............................
....OO..................OO...
....O.O..........OO....O.O...
.....O..........O.O.....O....
..O.............OO.........O.
..OOOOOO........O.....OOOOOO.
.......O..............O......
....OO..................OO...
....O....................O...
.....O..................O....
..OOO..O..............O..OOO.
..O..OOO........O.....OOO...O
...O............OO.......OOO.
....OO..........O.O.....O....
......O..........OO....O..OO.
....OO..................OO.O.
.O..O....................O...
O.O.O..OO............OO..O...
.O..O.O.O............O.O.OO..
....O.O................O..O..
.....OO................OO....
</a></pre></td></tr></table></center>
<p><a name=dock>:</a><b>dock</b> The following <a href="lex_i.htm#inductioncoil">induction coil</a>.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:.OOOO.$O....O$OO..OO$"
>.OOOO.
O....O
OO..OO
</a></pre></td></tr></table></center>
<p><a name=domino>:</a><b>domino</b> The 2-cell <a href="lex_p.htm#polyomino">polyomino</a>. A number of objects, such as the
<a href="lex_h.htm#hwss">HWSS</a> and <a href="lex_p.htm#pentadecathlon">pentadecathlon</a>, produce domino <a href="lex_s.htm#spark">sparks</a>.
<p><a name=dormant>:</a><b>dormant</b> An object that is either stable or oscillates without
producing any output, until it is <a href="lex_t.htm#trigger">triggered</a> by an appropriate
signal, which then produces some desired action. For example,
<a href="lex_f.htm#freezedried">freeze-dried</a> objects are dormant until the arrival of a particular
glider.
<p><a name=doseedo>:</a><b>do-see-do</b> The following reaction, found by David Bell in 1996, in
which two <a href="lex_g.htm#glider">gliders</a> appear to circle around each other as they are
reflected 90 degrees by a <a href="lex_t.htm#twinbeesshuttle">twin bees shuttle</a>. Four copies of the
reaction can be used to create a p92 glider loop which repeats the
do-see-do reaction forever.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:.....................................................O.O$.....................................................OO.$......................................................O.$........................................................$........................................................$........................................................$........................................................$........................................................$........................................................$........................................................$........................................................$........................................................$........................................................$........................................................$........................................................$........................................................$........................................................$........................................................$........................................................$................................................OO......$................................................O.......$..............................................O.O.......$..............................................OO........$..............................O.O.......................$..............................OO........................$...............................O........................$........................................................$.......................OOO..............................$OO........OOO........OO.O.OO............................$OO........O...O.....O.....OO............................$..........O....O.....OO.O.OO............................$...........O...O.......OOO..............................$........................................................$...........O...O........................................$..........O....O........................................$OO........O...O............OO...........................$OO........OOO..............OO...........................$"
>.....................................................O.O
.....................................................OO.
......................................................O.
........................................................
........................................................
........................................................
........................................................
........................................................
........................................................
........................................................
........................................................
........................................................
........................................................
........................................................
........................................................
........................................................
........................................................
........................................................
........................................................
................................................OO......
................................................O.......
..............................................O.O.......
..............................................OO........
..............................O.O.......................
..............................OO........................
...............................O........................
........................................................
.......................OOO..............................
OO........OOO........OO.O.OO............................
OO........O...O.....O.....OO............................
..........O....O.....OO.O.OO............................
...........O...O.......OOO..............................
........................................................
...........O...O........................................
..........O....O........................................
OO........O...O............OO...........................
OO........OOO..............OO...........................
</a></pre></td></tr></table></center>
<p><a name=doublebarrelled>:</a><b>double-barrelled</b> Of a <a href="lex_g.htm#gun">gun</a>, emitting two streams of <a href="lex_s.htm#spaceship">spaceships</a> (or
<a href="lex_r.htm#rake">rakes</a>) every period. For examples, see <a href="lex_b.htm#b52bomber">B-52 bomber</a>,
<a href="lex_s.htm#simkinglidergun">Simkin glider gun</a>, and <a href="lex_p.htm#p246gun">p246 gun</a>. In most cases, the two streams
are alternately emitted 1/2 period apart. It is also possible for
the two streams to be emitted simultaneously, as in this
double-barrelled glider gun by Bill Gosper:
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:.................O................................$.................OO...............................$..................OO..............................$.................OO...............................$................................O.................$...............................OO...............OO$..............................OO................OO$.................OO............OO.................$OO................OO..............................$OO...............OO...............................$.................O................................$...............................OO.................$..............................OO..................$...............................OO.................$................................O.................$"
>.................O................................
.................OO...............................
..................OO..............................
.................OO...............................
................................O.................
...............................OO...............OO
..............................OO................OO
.................OO............OO.................
OO................OO..............................
OO...............OO...............................
.................O................................
...............................OO.................
..............................OO..................
...............................OO.................
................................O.................
</a></pre></td></tr></table></center>
<p><a name=doubleblockreaction>:</a><b>double block reaction</b> A certain reaction that can be used to
stabilize the <a href="lex_t.htm#twinbeesshuttle">twin bees shuttle</a> (qv). This was discovered by David
Bell in October 1996.
<p>The same reaction sometimes works in other situations, as shown in
the following diagram where a pair of blocks eats an <a href="lex_r.htm#rpentomino">R-pentomino</a>
and a <a href="lex_l.htm#lwss">LWSS</a>. (The LWSS version was known at least as early 1994,
when Paul Callahan saw it form spontaneously as a result of firing an
LWSS stream at some random junk.)
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:.OOOO.....OO....$O...O......OO.OO$....O......O..OO$O..O............$................$.............OO.$.............OO.$"
>.OOOO.....OO....
O...O......OO.OO
....O......O..OO
O..O............
................
.............OO.
.............OO.
</a></pre></td></tr></table></center>
<p><a name=doublecaterer>:</a><b>double caterer</b> (p3) Found by Dean Hickerson, October 1989. Compare
<a href="lex_c.htm#caterer">caterer</a> and <a href="lex_t.htm#triplecaterer">triple caterer</a>.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:.....OO...O........$....O..O..OOO......$....OO.O.....O.....$......O.OOOO.O.....$..OOO.O.O...O.OO...$.O..O..O...O..O.O..$O.O..O...O.OO....O.$.O..........OO.OOO.$..OO.OO.OO...O.....$...O...O.....O.OOO.$...O...O......OO..O$.................OO$"
>.....OO...O........
....O..O..OOO......
....OO.O.....O.....
......O.OOOO.O.....
..OOO.O.O...O.OO...
.O..O..O...O..O.O..
O.O..O...O.OO....O.
.O..........OO.OOO.
..OO.OO.OO...O.....
...O...O.....O.OOO.
...O...O......OO..O
.................OO
</a></pre></td></tr></table></center>
<p><a name=doubleewe>:</a><b>double ewe</b> (p3) Found by Robert Wainwright before September 1971.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:......OO............$.......O............$......O.............$......OO............$.........OO.........$......OOO.O.........$O.OO.O..............$OO.O.O..............$.....O...O..........$....O...OO....OO....$....OO....OO...O....$..........O...O.....$..............O.O.OO$..............O.OO.O$.........O.OOO......$.........OO.........$............OO......$.............O......$............O.......$............OO......$"
>......OO............
.......O............
......O.............
......OO............
.........OO.........
......OOO.O.........
O.OO.O..............
OO.O.O..............
.....O...O..........
....O...OO....OO....
....OO....OO...O....
..........O...O.....
..............O.O.OO
..............O.OO.O
.........O.OOO......
.........OO.........
............OO......
.............O......
............O.......
............OO......
</a></pre></td></tr></table></center>
<p><a name=doublewing>:</a><b>double wing</b> = <a href="lex_m.htm#mooseantlers">moose antlers</a>. This term is no longer in use.
<p><a name=dove>:</a><b>dove</b> The following <a href="lex_i.htm#inductioncoil">induction coil</a>, found in 2015 to be a possible
active reaction for the input or output of a <a href="lex_c.htm#converter">converter</a>.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:.OO..$O..O.$.O..O$..OOO$"
>.OO..
O..O.
.O..O
..OOO
</a></pre></td></tr></table></center>
<p><a name=downboatwithtail>:</a><b>down boat with tail</b> = <a href="lex_c.htm#cisboatwithtail">cis-boat with tail</a>
<p><a name=dr>:</a><b>dr</b> Short identifier for Dean Hickerson's 'drifter' search program,
used at various times to find <a href="lex_w.htm#wire">wires</a>, <a href="lex_e.htm#eater">eaters</a>, higher-period
<a href="lex_b.htm#billiardtableconfiguration">billiard table configurations</a>, and related <a href="lex_s.htm#signal">signal</a>-carrying and
signal-processing mechanisms. See also <a href="#drifter">drifter</a>.
<p><a name=dragon>:</a><b>dragon</b> (<i>c</i>/6 orthogonally, p6) This <a href="lex_s.htm#spaceship">spaceship</a>, discovered by Paul
Tooke in April 2000, was the first known <a href="lex_c.htm#c6spaceship">c/6 spaceship</a>. With 102
cells, it was the smallest known orthogonal <i>c</i>/6 spaceship until
Hartmut Holzwart discovered <a href="lex_1.htm#a-56p6h1v0">56P6H1V0</a> in April 2009.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:.............O..OO......O..OOO$.....O...OOOO.OOOOOO....O..OOO$.OOOOO....O....O....OOO.......$O......OO.O......OO.OOO..O.OOO$.OOOOO.OOO........OOOO...O.OOO$.....O..O..............O......$........OO..........OO.OO.....$........OO..........OO.OO.....$.....O..O..............O......$.OOOOO.OOO........OOOO...O.OOO$O......OO.O......OO.OOO..O.OOO$.OOOOO....O....O....OOO.......$.....O...OOOO.OOOOOO....O..OOO$.............O..OO......O..OOO$"
>.............O..OO......O..OOO
.....O...OOOO.OOOOOO....O..OOO
.OOOOO....O....O....OOO.......
O......OO.O......OO.OOO..O.OOO
.OOOOO.OOO........OOOO...O.OOO
.....O..O..............O......
........OO..........OO.OO.....
........OO..........OO.OO.....
.....O..O..............O......
.OOOOO.OOO........OOOO...O.OOO
O......OO.O......OO.OOO..O.OOO
.OOOOO....O....O....OOO.......
.....O...OOOO.OOOOOO....O..OOO
.............O..OO......O..OOO
</a></pre></td></tr></table></center>
<p><a name=draintrap>:</a><b>drain trap</b> = <a href="lex_p.htm#paperclip">paperclip</a>. This term is no longer in use.
<p><a name=dread>:</a><b>D read</b> = <a href="#destructiveread">destructive read</a>
<p><a name=dried>:</a><b>dried</b> = <a href="lex_f.htm#freezedried">freeze-dried</a>.
<p><a name=drifter>:</a><b>drifter</b> A perturbation moving within a stable pattern. Dean
Hickerson has written a <a href="lex_s.htm#searchprogram">search program</a> to search for drifters, with
the hope of finding one which could be moved around a track. Because
drifters can be very small, they could be packed more tightly than
<a href="lex_h.htm#herschel">Herschels</a>, and so allow the creation of <a href="lex_o.htm#oscillator">oscillators</a> of periods
not yet attained, and possibly prove that Life is <a href="lex_o.htm#omniperiodic">omniperiodic</a>.
Hickerson has found a number of components towards this end, but it
has proved difficult to change the direction of movement of a
drifter, and so far no complete track has been found. However,
Hickerson has had success using the same program to find <a href="lex_e.htm#eater">eaters</a>
with novel properties, such as <a href="lex_s.htm#sparkingeater">sparking eaters</a> and the ones shown
in <a href="#diuresis">diuresis</a>.
<p><a name=dual1234>:</a><b>dual 1-2-3-4</b> = <a href="lex_a.htm#achimsp4">Achim's p4</a>
<p><a name=duoplet>:</a><b>duoplet</b> A diagonal two-bit spark produced by many oscillators and
eater reactions. Among other uses, it can reflect gliders 90
degrees. The following pattern shows an <a href="lex_e.htm#eater5">eater5</a> eating gliders and
producing duoplets which are then used to reflect a separate glider
stream. If only one glider is present, the eater5 successfully
absorbs it, so this mechanism may be considered to be a simple AND
gate.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:..O....................$O.O....................$.OO....................$.......................$.......................$.......O...............$.....O.O...............$......OO...............$.....................O.$....................O..$....................OOO$.......................$.......................$................O......$...............O.......$...............OOO.....$.......................$....................OO.$................O...OO.$...............O.O.....$..............O.O......$..............O........$.............OO........$"
>..O....................
O.O....................
.OO....................
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.......O...............
.....O.O...............
......OO...............
.....................O.
....................O..
....................OOO
.......................
.......................
................O......
...............O.......
...............OOO.....
.......................
....................OO.
................O...OO.
...............O.O.....
..............O.O......
..............O........
.............OO........
</a></pre></td></tr></table></center>
<p><a name=dyingspark>:</a><b>dying spark</b> See <a href="lex_s.htm#spark">spark</a>. A spark by definition dies out completely
after some number of ticks.
<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>
|
