.\" This file is (c) 1998-2001 Ted Faber (faber@lunabase.org) see COPYRIGHT
.\" for the full copyright and limitations of liabilities.
.EQ
delim $$
.EN
.PP
This is a collection of example graphs that are mostly taken from
Bentley and Kernighan's paper on
.I grap
that is referenced from the manual page.  Please check that for an
explanation of the graphs' meaning.  I use them primarily as a
regression test suite.
.PP
Each graph is accompanied by a brief description and the 
.I grap
code that produced it.
.KS
.PP
A simple copy.  The data is the winning time for the mens' 400m run
taken from the Pittsburgh Press's 
.I
1994 World Almanac and Book of Facts.
.R
.EQ
delim off
.EN
.DS
.ft CW
\&.G1
\&copy "400mtimes.d"
\&.G2
.ft
.DE
.EQ
delim $$
.EN
.G1
copy "400mtimes.d"
.G2
.KE
.KS
.PP
A simple copy with both $x$ and $y$ coordinates.  The data is from the
same source, but includes the year.
.EQ
delim off
.EN
.DS
.ft CW
\&.G1
\&copy "400mpairs.d"
\&.G2
.ft
.DE
.EQ
delim $$
.EN
.G1
copy "400mpairs.d"
.G2
Simple connection of points.  Same data.
.EQ
delim off
.EN
.DS
.ft CW
\&.G1
\&draw solid
\&copy "400mpairs.d"
\&.G2
.ft
.DE
.EQ
delim $$
.EN
.G1
draw solid
copy "400mpairs.d"
.G2
.KE
.KS
.PP
Spruced up a bit.  We add axis labels and remove some frame
boundaries.  Note that my version of 
.I grap
positions left and right axis labels parallel to the axis.  That
feature can be disabled by specifying
.CW unaligned
as a justification for the label.  The same data is used.
.EQ
delim off
.EN
.DS
.ft CW
\&.G1
\&frame invis ht 2 wid 3 left solid bot solid
\&label left "Time (in seconds)" left .25
\&label bot "Olympic 400 Meter Run: Winning Times"
\&draw solid
\&copy "400mpairs.d"
\&.G2
.ft
.DE
.EQ
delim $$
.EN
.G1
frame invis ht 2 wid 3 left solid bot solid
label left "Time (in seconds)" left .25
label bot "Olympic 400 Meter Run: Winning Times"
draw solid
copy "400mpairs.d"
.G2
.KE
.KS
.PP
User specified axes, and a font change in the graph.  
You must restore the
font after the terminating 
.CW .G2 .
Commands to 
.I groff
or 
.I pic
are issued at the same place relative to other 
.I grap
commands in the file (as of version 1.50).  The frame is drawn before
the first plotted element (invisible lines count) or when the frame
statement is executed.
.EQ
delim off
.EN
.DS
.ft CW
\&.G1
\&.ft H
\&frame invis ht 2 wid 3 left solid bot solid
\&label left "Time (in seconds)" left .25
\&label bot "Olympic 400 Meter Run: Winning Times"
\&coord x 1894, 1994 y 42, 56
\&draw solid
\&copy "400mpairs.d"
\&.G2
.ft
.DE
.EQ
delim $$
.EN
.G1
.ft H
frame invis ht 2 wid 3 left solid bot solid
label left "Time (in seconds)" left .25
label bot "Olympic 400 Meter Run: Winning Times"
coord x 1894, 1994 y 42, 56
draw solid
copy "400mpairs.d"
.G2
.KE
.KS
.PP
User specified tick placement, and a return to the Roman font.  Same data.
.EQ
delim off
.EN
.DS
.ft CW
\&.G1
\&frame invis ht 2 wid 3 left solid bot solid
\&label left "Time (in seconds)" left .25
\&label bot "Olympic 400 Meter Run: Winning Times"
\&coord x 1894, 1994 y 42, 56
\&ticks left out at 44 "44", 46, 48 "48", 50, 52 "52", 54
\&ticks bot in from 1900 to 1980 by 20
\&draw solid
\&copy "400mpairs.d"
\&.G2
.ft
.DE
.EQ
delim $$
.EN
.G1
frame invis ht 2 wid 3 left solid bot solid
label left "Time (in seconds)" left .25
label bot "Olympic 400 Meter Run: Winning Times"
coord x 1894, 1994 y 42, 56
ticks left out at 44 "44", 46, 48 "48", 50, 52 "52", 54
ticks bot in from 1900 to 1980 by 20
draw solid
copy "400mpairs.d"
.G2
.KE
.KS
.PP
This graph adds the women's times (from the same source) and includes
different plotting styles and labels.  My version of this graph also
uses the 
.CW until
keyword to include the data rather than external
files.  
.CW until
appears before and after the macro definition.
.EQ
delim off
.EN
.DS
.ft CW
\&.G1
\&frame invis ht 2 wid 3 left solid bot solid
\&label left "Time (in seconds)"
\&label bot "Olympic 400 Meter Run: Winning Times"
\&coord x 1894, 1994 y 42, 56
\&ticks left out at 44 , 46 "", 48, 50 "", 52, 54 ""
\&ticks bot in from 1900 to 1980 by 20
\&draw solid
\&copy until "END" thru {next at $1, $2;}
\&1896 54.2
\&1900 49.4
\&[...]
\&1992 43.50
\&END
\&new dotted
\&copy until "END" 
\&1964 52.
\&1968 52.
\&[...]
\&1992 48.83
\&END
\&"Women"  size -3 at 1958,52
\&"Men" size -3 at 1910,47
\&.G2
.ft
.DE
.EQ
delim $$
.EN
.G1
frame invis ht 2 wid 3 left solid bot solid
label left "Time (in seconds)"
label bot "Olympic 400 Meter Run: Winning Times"
coord x 1894, 1994 y 42, 56
ticks left out at 44 , 46 "", 48, 50 "", 52, 54 ""
ticks bot in from 1900 to 1980 by 20
draw solid
copy until "END" thru {next at $1, $2;}
1896 54.2
1900 49.4
1904 49.2
1908 50
1912 48.2
1920 49.6
1924 47.6
1928 47.8
1932 46.2
1936 46.5
1948 46.2
1952 45.9
1956 46.7
1960 44.9
1964 45.1
1968 43.8
1972 44.66
1976 44.26
1980 44.60
1984 44.27
1988 43.87
1992 43.50
END
new dotted
copy until "END" 
1964 52.
1968 52.
1972 51.08
1976 49.29
1980 48.88
1984 48.83
1988 48.95
1992 48.83
END
"Women"  size -3 at 1958,52
"Men" size -3 at 1910,47
.G2
.KE
.KS
.PP
Another simple copy.  Bentley and Kernighan use phone installations, I
use numbers of hosts on the Internet.  The data is from 
.CW ftp://nic.merit.edu/nsfnet/statistics/history.hosts ,
maintained by:
.DS 
Merit Network
4251 Plymouth Road
Suite C
Ann Arbor, MI 48105-2785
734-764-9430
.DE
.EQ
delim off
.EN
.DS
.ft CW
\&.G1
\&copy "internet.d"
\&.G2
.ft
.DE
.EQ
delim $$
.EN
.G1
copy "internet.d"
.G2
.KE
.KS
.PP
The same data plotted on a logarithmic $y$ scale, and rescaled to
megahosts, which is less humorous than megaphones.  The placement of
the bottom ticks shows the 
.CW
from .. to .. by
.R
construct.  The filename is given after the macro for variety (and to
test that feature).
.EQ
delim off
.EN
.DS
.ft CW
\&.G1
\&coord x 80,100 y 1e-4, 30 log y
\&ticks bot at 80 "1980", 100 "2000"
\&ticks bot from 85 to 95 by 5 "' %g"
\&ticks left 
\&label left "Millions of Hosts" left .25
\&label bot "Year"
\&draw solid
\&copy thru { next at $1, $2/1e6;} "internet.d" 
\&.G2
.ft
.DE
.EQ
delim $$
.EN
.G1
coord x 80,100 y 1e-4, 30 log y
ticks bot at 80 "1980", 100 "2000"
ticks bot from 85 to 95 by 5 "' %g"
ticks left 
label left "Millions of Hosts" left .25
label bot "Year"
draw solid
copy thru { next at $1, $2/1e6;} "internet.d"
.G2
.KE
.KS
.PP
A demo of 
.I grap 's
annotation abilities, mostly.  The data is all in the graph specification.
.EQ
delim off
.EN
.DS
.ft CW
\&.G1
\&frame ht 2 wid 2
\&coord x 0,100 y 0,100
\&grid bot dotted from 20 to 80 by 20
\&grid left dotted from 20 to 80 by 20
\&
\&"Text above" above at 50,50
\&"Text rjust   " rjust at 50,50
\&bullet at 80,90
\&vtick at 80,80
\&box at 80,70
\&times at 80,60
\&
\&circle at 50,50
\&circle at 50,80 radius .25
\&line dashed from 10,90 to 30,90
\&arrow from 10,70 to 30,90
\&
\&draw A solid
\&draw B dashed delta
\&next A at 10,10
\&next B at 10,20
\&next A at 50,20
\&next A at 90,10
\&next B at 50,30
\&next B at 90,30
\&.G2
.ft
.DE
.EQ
delim $$
.EN
.G1
frame ht 2 wid 2
coord x 0,100 y 0,100
grid bot dotted from 20 to 80 by 20
grid left dotted from 20 to 80 by 20

"Text above" above at 50,50
"Text rjust   " rjust at 50,50
bullet at 80,90
vtick at 80,80
box at 80,70
times at 80,60

circle at 50,50
circle at 50,80 radius .25
line dashed from 10,90 to 30,90
arrow from 10,70 to 30,90

draw A solid
draw B dashed delta
next A at 10,10
next B at 10,20
next A at 50,20
next A at 90,10
next B at 50,30
next B at 90,30
.G2
.KE
.KS
.PP
A simple macro demo.  Again, no data.
.EQ
delim off
.EN
.DS
.ft CW
\&.G1
\&frame ht 1.5 wid 1.5
\&define square {($1) * ($1)}
\&define root {($1)^.5 }
\&define P {
\&	times at i, square(i); i = i +1;
\&	circle at j, root(j); j= j+5;
\&}
\&i = 1; j = 5
\&P; P; P; P; P
\&.G2
.ft
.DE
.EQ
delim $$
.EN
.G1
frame ht 1.5 wid 1.5
define square {($1) * ($1)}
define root {($1)^.5 }
define P {
	times at i, square(i); i = i +1;
	circle at j, root(j); j= j+5;
}
i = 1; j = 5
P; P; P; P; P
.G2
.KE
.KS
.PP
The number of Representatives to the U.S. Congress versus population
of the states.  My data is more recent than that of Bentley/Kernighan,
so the graph is different from theirs.  Data is from the U.S. Census
Bureau at 
.CW http://www.census.gov/ , 
specifically
.CW http://www.census.gov/population/www/censusdata/apportionment.html .
.EQ
delim off
.EN
.DS
.ft CW
\&.G1
\&label left "Representatives to Congress"
\&label bot "Population (Millions)"
\&coord x .3, 35 y .8, 60 log log
\&define PlotState { circle at $3/1e6, $2; }
\&copy "states.d" thru PlotState
\&.G2
.ft
.DE
.EQ
delim $$
.EN
.G1
label left "Representatives to Congress"
label bot "Population (Millions)"
coord x .3, 35 y .8, 60 log log
define PlotState { circle at $3/1e6, $2; }
copy "states.d" thru PlotState
.G2
.KE
.KS
.PP
A 2-axis plot.  We redefine square because the macro example graph
changed it.  I advise against changing the predefined macro
definitions because macros persist across graphs.  The same data is
plotted.
.EQ
delim off
.EN
.DS
.ft CW
\&.G1
\&define square {"\\s-2\\(sq\\s0"}
\&frame ht 3 wid 3.5
\&label left "Population in Millions (Plotted as \\(bu)"
\&label bot "Rank in Population"
\&label right "Representatives (Plotted as \\(sq)"
\&coord pop x 0,51 y .2,35 log y
\&coord rep x 0,51 y .3,100 log y
\&ticks left out at pop .3,1,3,10,30
\&ticks bot out at pop 1,50
\&ticks right out at rep 1,3,10,30,100
\&thisrank = 50
\&copy "states.d" thru {
\&	bullet at pop thisrank,$3/1e6
\&	square at rep thisrank,$2
\&	thisrank = thisrank -1
\&}
\&.G2
.ft
.DE
.EQ
delim $$
.EN
.G1
define square {"\s-2\(sq\s0"}
frame ht 3 wid 3.5
label left "Population in Millions (Plotted as \(bu)"
label bot "Rank in Population"
label right "Representatives (Plotted as \(sq)"
coord pop x 0,51 y .2,35 log y
coord rep x 0,51 y .3,100 log y
ticks left out at pop .3,1,3,10,30
ticks bot out at pop 1,50
ticks right out at rep 1,3,10,30,100
thisrank = 50
copy "states.d" thru {
	bullet at pop thisrank,$3/1e6
	square at rep thisrank,$2
	thisrank = thisrank -1
}
.G2
.KE
.KS
.PP
A sine wave plotted by a 
.CW for
loop with \(*p calculated with the internal
.CW atan2()
function.  No data.
.EQ
delim off
.EN
.DS
.ft CW
\&.G1
\&frame ht 1 wid 3
\&draw solid
\&pi = atan2(0,-1)
\&for i from 0 to 2* pi by .1 do { next at i, sin(i); }
\&.G2
.ft
.DE
.EQ
delim $$
.EN
.G1
frame ht 1 wid 3
draw solid
pi = atan2(0,-1)
for i from 0 to 2* pi by .1 do { next at i, sin(i); }
.G2
.KE
.KS
.PP
Bentley and Kernighan do this graph with Kentucky Derby winning times.
I don't have them, so I used the 400m times again.  My program is
slightly different because the 400m run times have gaps.
.EQ
delim off
.EN
.DS
.ft CW
\&.G1
\&label left "Winning Time" left .3
\&label bot "Olympics Men's 400 m"
\&bestsofar = 1000
\&anchor = 0
\&copy "400mpairs.d" thru {
\&	bullet at $1,$2
\&	if ( anchor != 0 ) then { 
\&		line from anchor, bestsofar to $1,bestsofar
\&	}
\&	bestsofar = min(bestsofar,$2)
\&	if ( bestsofar == $2 ) then { 
\&		anchor = $1
\&	}
\&}
\&.G2
.ft
.DE
.EQ
delim $$
.EN
.G1
label left "Winning Time" left .3
label bot "Olympics Men's 400 m"
bestsofar = 1000
anchor = 0
copy "400mpairs.d" thru {
	bullet at $1,$2
	if ( anchor != 0 ) then { 
		line from anchor, bestsofar to $1,bestsofar
	}
	bestsofar = min(bestsofar,$2)
	if ( bestsofar == $2 ) then { 
		anchor = $1
	}
}
.G2
.KE
.KS
.PP
Bentley and Kernighan discuss the regression and modeling that these
graphs reflect.  The data is the U.S. population from the U.S. Census
bureau.  This shows off the ability to place two plots relative to
each other using the 
.CW graph
statement.
.EQ
delim off
.EN
.DS
.ft CW
\&.G1
\&graph Linear
\&coord x 1785, 1955 y 0, 160
\&label left "Population in Millions" left .3
\&label right "Linear Scale" unaligned "Linear Fit" right .4
\&ticks bot off
\&copy "usapop.d"
\&define fit { 35 + 1.4 * ($1-1870) }
\&line from 1850, fit(1850) to 1950,fit(1950)
\&graph Exponential with .Frame.n at Linear.Frame.s - (0, .05)
\&coord x 1785, 1955 y 3, 160 log y
\&label left "Population in Millions" left .3
\&label right "Logarithmic Scale" unaligned "Exponential Fit" right .4
\&copy "usapop.d"
\&define fit { exp(.75 + .012 * ($1-1800)) }
\&line from 1790, fit(1790) to 1920,fit(1920)
\&.G2
.ft
.DE
.EQ
delim $$
.EN
.G1
graph Linear
coord x 1785, 1955 y 0, 160
label left "Population in Millions" left .3
label right "Linear Scale" unaligned "Linear Fit" right .4
ticks bot off
copy "usapop.d"
define fit { 35 + 1.4 * ($1-1870) }
line from 1850, fit(1850) to 1950,fit(1950)
graph Exponential with .Frame.n at Linear.Frame.s - (0, .05)
coord x 1785, 1955 y 3, 160 log y
label left "Population in Millions" left .3
label right "Logarithmic Scale" unaligned "Exponential Fit" right .4
copy "usapop.d"
define fit { exp(.75 + .012 * ($1-1800)) }
line from 1790, fit(1790) to 1920,fit(1920)
.G2
.KE
.KS
.PP
Another re-expression of the U.S. population data.  Uses plenty of
.I grap 
arithmetic and an 
.I eqn
axis label (which is 
.CW unaligned ).
.EQ
delim off
.EN
.DS
.ft CW
\&.G1
\&label left "Population in Millions" left .3
\&label right "$x$ re-expressed as" unaligned "" "$space 0 left  
\&	( { date -1600 } over 100 right ) sup 7$" right .4
\&define newx { exp(7*(log(($1-1600)/100))) }
\&ticks bot out at newx(1800) "1800", newx(1850) "1850", \\
\&	newx(1900) "1900"
\&copy "usapop.d" thru {
\&	if $1 <= 1900 then { bullet at newx($1),$2 }
\&}
\&.G2
.ft
.DE
.EQ
delim $$
.EN
.G1
label left "Population in Millions" left .3
label right "$x$ re-expressed as" unaligned "" "$space 0 left ( { date -1600 } over 100 right ) sup 7$" right .4
define newx { exp(7*(log(($1-1600)/100))) }
ticks bot out at newx(1800) "1800", newx(1850) "1850", \
	newx(1900) "1900"
copy "usapop.d" thru {
	if $1 <= 1900 then { bullet at newx($1),$2 }
}
.G2
.KE
.KS
.PP
A simple copy of a multiple field data file.  The data is the 5th,
50th, and 95th percentiles for the heights of boys in America at
different ages.  The data is reported from Thomas J. Glover's
remarkable
.I Pocket 
.I Ref ,
which reports data from the National Center for Health Statistics.  
.I
Pocket Ref
.R
is published by Sequoia Publishing, Littleton, CO.
.EQ
delim off
.EN
.DS
.ft CW
\&.G1
\&copy "boyhts.d"
\&.G2
.ft
.DE
.EQ
delim $$
.EN
.G1
copy "boyhts.d"
.G2
.KE
.KS
.PP
The same data with a linear regression, and the 90% confidence
intervals drawn as lines.  Note the cascading assignment
statements (patch courtesy of Bruce Lilly).  (Bentley and
Kernighan's data is in centimeters, mine is in inches, so a different
conversion to feet is used.)
.EQ
delim off
.EN
.DS
.ft CW
\&.G1
\&label left "Heights in Feet"
\&label bot "Heights of Boys in the US Ages 2-18"
\&cmpft = 12
\&minx = 1e12; maxx = -1e12
\&n = sigx = sigx2 = sigy = sigxy = 0;
\&copy "boyhts.d" thru {
\&	line from $1, $2/cmpft to $1, $4/cmpft
\&	ty = $3 / cmpft
\&	bullet at $1, ty
\&	n = n+1
\&	sigx = sigx + $1; sigx2 = sigx2 + $1 * $1
\&	sigy = sigy + ty; sigxy = sigxy + $1*ty
\&	minx = min(minx,$1); maxx = max(maxx,$1);
\&}
\&slope = ( n*sigxy - sigx* sigy) / (n*sigx2 - sigx * sigx)
\&inter = ( sigy - slope * sigx) / n
\&line from minx, slope * minx+inter to maxx, slope * maxx + inter
\&.G2
.ft
.DE
.EQ
delim $$
.EN
.G1
label left "Heights in Feet"
label bot "Heights of Boys in the US Ages 2-18"
cmpft = 12
minx = 1e12; maxx = -1e12
n = sigx = sigx2 = sigy = sigxy = 0;
copy "boyhts.d" thru {
	line from $1, $2/cmpft to $1, $4/cmpft
	ty = $3 / cmpft
	bullet at $1, ty
	n = n+1
	sigx = sigx + $1; sigx2 = sigx2 + $1 * $1
	sigy = sigy + ty; sigxy = sigxy + $1*ty
	minx = min(minx,$1); maxx = max(maxx,$1);
}
slope = ( n*sigxy - sigx* sigy) / (n*sigx2 - sigx * sigx)
inter = ( sigy - slope * sigx) / n
line from minx, slope * minx+inter to maxx, slope * maxx + inter
.G2
.KE
.KS
.PP
This is a 4 linestyle plot with a copy statement that adds labels.
The scales are user-defined, and the $y$ axis is logarithmic.  The
data is the number of male and female officers and enlisted personnel
in the U.S. Armed forces from 1940-1993 from the Pittsburgh Press 
.I 
World Almanac and Book of Facts.
.R
This graph has more data than the equivalent from Bentley and Kernighan.
.EQ
delim off
.EN
.DS
.ft CW
\&.G1
\&coord x 38, 95 y .8, 10000 log y
\&label bot "U.S. Military Personnel"
\&label left "Thousands" left .25
\&draw of solid
\&draw ef dashed
\&draw om dotted
\&draw em solid
\&copy "army.d" thru {
\&	next of at $1, $3
\&	next ef at $1, $5
\&	next om at $1, $2
\&	next em at $1, $4
\&}
\&copy until "XXX" thru { "$1 $2" size -3 at 60, $3; }
\&Enlisted Men 1200
\&Male Officers 140
\&Enlisted Women 12
\&Female Officers 2.5
\&XXX
\&.G2
.ft
.DE
.EQ
delim $$
.EN
.G1
coord x 38, 95 y .8, 10000 log y
label bot "U.S. Military Personnel" 
label left "Thousands" left .25
draw of solid
draw ef dashed
draw om dotted
draw em solid
copy "army.d" thru {
	next of at $1, $3
	next ef at $1, $5
	next om at $1, $2
	next em at $1, $4
}
copy until "XXX" thru { "$1 $2" size -3 at 60, $3; }
Enlisted Men 1200
Male Officers 140
Enlisted Women 12
Female Officers 2.5
XXX
.G2
.KE
.KS
.PP
Obfuscation of data via scatter plots.  Three aligned graphs are
produced that plot the numbers of enlisted men as functions of male
officers, female officers, and enlisted women.  The plotting symbol is
the year in question.  Same data as above.
.EQ
delim off
.EN
.DS
.ft CW
\&.G1
\&graph A 
\&frame ht 1.6667 wid 1.6667
\&label bot "Male_Officers"
\&label left "Enlisted_Men"
\&coord log log
\&ticks off
\&copy "army.d" thru { "\s-3$1\s+3" at $2,$4; }
\&graph A with .Frame.w at A.Frame.e +(.1,0)
\&frame ht 1.6667 wid 1.6667
\&label bot "Female_Officers"
\&coord log log
\&ticks off
\&copy "army.d" thru { "\s-3$1\s+3" at $3,$4; }
\&graph A with .Frame.w at A.Frame.e +(.1,0)
\&frame ht 1.6667 wid 1.6667
\&label bot "Enlisted_Women"
\&coord log log
\&ticks off
\&copy "army.d" thru { "\s-3$1\s+3" at $5,$4; }
\&.G2
.ft
.DE
.EQ
delim $$
.EN
.G1
graph A 
frame ht 1.6667 wid 1.6667
label bot "Male_Officers"
label left "Enlisted_Men"
coord log log
ticks off
copy "army.d" thru { "\s-3$1\s+3" at $2,$4; }
graph A with .Frame.w at A.Frame.e +(.1,0)
frame ht 1.6667 wid 1.6667
label bot "Female_Officers"
coord log log
ticks off
copy "army.d" thru { "\s-3$1\s+3" at $3,$4; }
graph A with .Frame.w at A.Frame.e +(.1,0)
frame ht 1.6667 wid 1.6667
label bot "Enlisted_Women"
coord log log
ticks off
copy "army.d" thru { "\s-3$1\s+3" at $5,$4; }
.G2
.KE
.KS
.PP
One of my favorites.  The solution of a differential equation and the
slope field it passes through.  It shows off nested 
.CW for
loops (one using = as a synonym for from) and 
.I eqn
labels.  The data is in the graph description.
.EQ
delim off
.EN
.DS
.ft CW
\&.G1
\&frame ht 2.5 wid 2.5
\&coord x 0,1 y 0,1
\&label bot "Direction Field is $y prime = x sup 2 / y$"
\&label left "$y = sqrt { ( 2 x sup 3 + 1 ) / 3 }$"
\&ticks left in 0 left .1 at 0,1
\&ticks bot in 0 down .1 at 0,1
\&len = .04
\&for tx from .01 to .91 by .1 do {
\&	for ty from .01 to .91 by .1 do {
\&		deriv = tx*tx/ty
\&		scale = len / sqrt(1 + deriv*deriv)
\&		line from tx,ty to tx+scale, ty+scale*deriv
\&	}
\&}
\&draw solid
\&for tx = 0 to 1 by .05 do {
\&	next at tx, sqrt((2*tx*tx*tx+1)/3)
\&}
\&.G2
.ft
.DE
.EQ
delim $$
.EN
.G1
frame ht 2.5 wid 2.5
coord x 0,1 y 0,1
label bot "Direction Field is $y prime = x sup 2 / y$"
label left "$y = sqrt { ( 2 x sup 3 + 1 ) / 3 }$"
ticks left in 0 left .1 at 0,1
ticks bot in 0 down .1 at 0,1
len = .04
for tx from .01 to .91 by .1 do {
	for ty from .01 to .91 by .1 do {
		deriv = tx*tx/ty
		scale = len / sqrt(1 + deriv*deriv)
		line from tx,ty to tx+scale, ty+scale*deriv
	}
}
draw solid
for tx = 0 to 1 by .05 do {
	next at tx, sqrt((2*tx*tx*tx+1)/3)
}
.G2
.KE
.KS
.PP
More population studies.  State population rank vs. population, with
the population on a log scale.  A regression line is also plotted.  I
used the same line as Bentley and Kernighan, although my data is more
recent.  The top labels are generated by a series of macros, the frame
size is enlarged, and the plotting symbol is the state abbreviation.
This graph uses the same census data as above.
.EQ
delim off
.EN
.DS
.ft CW
\&.G1
\&frame wid 5 ht 4
\&label left "Rank in Population"
\&label bot "Population (in Millions)"
\&label top "$log sub 2$ Population"
\&coord x .3, 35 y 0, 51 log x
\&define L { (2.0^$1)/1e6 "$1" }
\&ticks bot out at .5, 1, 2, 5, 10, 20
\&ticks left out from 10 to 50 by 10
\&ticks top out at L(19), L(20), L(21), L(22), L(23), L(24), L(25)
\&thisy = 50
\&copy "states.d" thru {
\&	"$1" size -4 at $3/1e6, thisy
\&	thisy = thisy-1
\&}
\&line dotted from 15.3,1 to .515, 50
\&.G2
.ft
.DE
.EQ
delim $$
.EN
.G1
frame wid 5 ht 4
label left "Rank in Population"
label bot "Population (in Millions)"
label top "$log sub 2$ Population"
coord x .3, 35 y 0, 51 log x
define L { (2.0^$1)/1e6 "$1" }
ticks bot out at .5, 1, 2, 5, 10, 20
ticks left out from 10 to 50 by 10
ticks top out at L(19), L(20), L(21), L(22), L(23), L(24), L(25)
thisy = 50
copy "states.d" thru {
	"$1" size -4 at $3/1e6, thisy
	thisy = thisy-1
}
line dotted from 15.3,1 to .515, 50
.G2
.KE
.KS
.PP
A nearly useless plot of the populations of different states.  Same data.
.EQ
delim off
.EN
.DS
.ft CW
\&.G1
\&frame invis ht .3 wid 5 bottom solid
\&label bot "Populations (in Millions) of the 50 States"
\&coord x .3, 35 y 0, 1 log x
\&ticks bot out at .5, 1, 2, 5, 10, 20
\&ticks left off
\&copy "states.d" thru { vtick at $3/1e6, .5; }
\&.G2
.ft
.DE
.EQ
delim $$
.EN
.G1
frame invis ht .3 wid 5 bottom solid
label bot "Populations (in Millions) of the 50 States"
coord x .3, 35 y 0, 1 log x
ticks bot out at .5, 1, 2, 5, 10, 20
ticks left off
copy "states.d" thru { vtick at $3/1e6, .5; }
.G2
.KE
.KS
.PP
A slight improvement, as the states are spread out and plotted with
their symbols.  The 
.CW rand() 
function is used to position them vertically, which shows off the
function, but doesn't guarantee a legible graph.  Same data.
.EQ
delim off
.EN
.DS
.ft CW
\&.G1
\&frame invis ht 1 wid 5 bottom solid
\&label bot "Populations (in Millions) of the 50 States"
\&coord x .3, 35 y 0, 1000 log x
\&ticks bot out at .5, 1, 2, 5, 10, 20
\&ticks left off
\&copy "states.d" thru { "$1" size -4 at $3/1e6, 100+900*rand(); }
\&.G2
.ft
.DE
.EQ
delim $$
.EN
.G1
frame invis ht 1 wid 5 bottom solid
label bot "Populations (in Millions) of the 50 States"
coord x .3, 35 y 0, 1000 log x
ticks bot out at .5, 1, 2, 5, 10, 20
ticks left off
copy "states.d" thru { "$1" size -4 at $3/1e6, 100+900*rand(); }
.G2
.KE
.KS
.PP
A histogram of the same data.  The input file is a result of running
the census data through the 
.I awk
script that Bentley and Kernighan describe.
.EQ
delim off
.EN
.DS
.ft CW
\&.G1
\&frame invis bot solid
\&label bot "Populations (in Millions) of the 50 States"
\&label left "Number of States" left .1
\&ticks bot out from 0 to 35 by 5
\&coord x 0, 35 y 0, 13
\&copy "states2.d" thru {
\&	line from $1,0 to $1,$2
\&	line from $1, $2 to $1+1, $2
\&	line from $1+1,$2 to $1+1,0
\&}
\&.G2
.ft
.DE
.EQ
delim $$
.EN
.G1
frame invis bot solid
label bot "Populations (in Millions) of the 50 States"
label left "Number of States" left .1
ticks bot out from 0 to 35 by 5
coord x 0, 35 y 0, 13
copy "states2.d" thru {
	line from $1,0 to $1,$2
	line from $1, $2 to $1+1, $2
	line from $1+1,$2 to $1+1,0
}
.G2
.KE
.KS
.PP
A \*Qlolliplot \*U histogram of the same data.
.EQ
delim off
.EN
.DS
.ft CW
\&.G1
\&frame invis bot solid
\&label bot "Populations (in Millions) of the 50 States"
\&label left "Number of States" left .1
\&ticks bot out from 0 to 35 by 5
\&coord x 0, 35 y 0, 13
\&copy "states2.d" thru {
\&	line dotted from $1+.5,0 to $1+.5,$2
\&	"\(bu" size +3 at $1+.5, $2
\&}
\&.G2
.ft
.DE
.EQ
delim $$
.EN
.G1
frame invis bot solid
label bot "Populations (in Millions) of the 50 States"
label left "Number of States" left .1
ticks bot out from 0 to 35 by 5
coord x 0, 35 y 0, 13
copy "states2.d" thru {
	line dotted from $1+.5,0 to $1+.5,$2
	"\(bu" size +3 at $1+.5, $2
}
.G2
.KE
.KS
.PP
A histogram of state abbreviations.  The data has been massaged by the
.I awk
program described by Bentley and Kernighan.
.EQ
delim off
.EN
.DS
.ft CW
\&.G1
\&frame invis wid 4 ht 2.5 bot solid
\&label bot "Populations (in Millions) of the 50 States"
\&ticks bot out from 0 to 35 by 5
\&ticks left off
\&coord x 0, 35 y 0, 13
\&copy "states3.d" thru {"$1" size -4 at $2+.5, $3+.5; }
\&.G2
.ft
.DE
.EQ
delim $$
.EN
.G1
frame invis wid 4 ht 2.5 bot solid
label bot "Populations (in Millions) of the 50 States"
ticks bot out from 0 to 35 by 5
ticks left off
coord x 0, 35 y 0, 13
copy "states3.d" thru {"$1" size -4 at $2+.5, $3+.5; }
.G2
.KE
.KS
.PP
A bar graph of profiler output.  The output is from running 
.I grap
on this file.
.EQ
delim off
.EN
.DS
.ft CW
\&.G1
\&ticks left off
\&cury = 0
\&barht = .7
\&copy "prof2.d" thru {
\&	line from 0,cury to $1, cury
\&	line from $1, cury to $1, cury-barht
\&	line from 0, cury-barht to $1, cury-barht
\&	"  $2" ljust at 0, cury-barht/2
\&	cury = cury-1
\&}
\&line from 0,0 to 0,cury+1-barht
\&bars = -cury
\&frame invis ht bars/3 wid 3
\&.G2
.ft
.DE
.EQ
delim $$
.EN
.G1
ticks left off
cury = 0
barht = .7
copy "prof2.d" thru {
	line from 0,cury to $1, cury
	line from $1, cury to $1, cury-barht
	line from 0, cury-barht to $1, cury-barht
	"  $2" ljust at 0, cury-barht/2
	cury = cury-1
}
line from 0,0 to 0,cury+1-barht
bars = -cury
frame invis ht bars/3 wid 3
.G2
.KE
.KS
.PP
The creative graph of state heights and volcano heights from their
grap paper.  The data was included in the graph description, which
(according to Bruce Lilly) is from John W. Tukey's classic 1977 text 
.I
Exploratory
Data Analysis,
.R
Chapter 10.  Tukey cites \*QThe World Almanac, 1966, page 269.  Their
source: National Geographic Society.\*U  The format of the graph is
also similar to a graph on pg. 40 (exhibit 5, chapter 2).  All those
attributions are from Bruce Lilly.  I don't have the relevant material
to verify it, but have no reason to doubt the accuracy of the information.
.EQ
delim off
.EN
.DS
.ft CW
.ps 8
.vs 10
\&.G1
\&frame invis ht 4 wid 3 bot solid
\&ticks off
\&coord x .5, 3.5 y 0,25
\&define Ht { "- $1,000 -" size -3 at 2, $1 }
\&Ht(5); Ht(10); Ht(15); Ht(20);
\&"Highest Point" "in 50 States" at 1,23
\&"Heights of" "219 Volcanos" at 3,23
\&"Feet" at 2,21.5; arrow from 2,22.5 to 2,24
\&define box {
\&	xc = $1; xl = xc - boxwidth/2; xh = xc+boxwidth/2
\&	y1 = $2; y2 = $3; y3 = $4; y4= $5; y5 = $6
\&	bullet at xc,y1
\&	"  $7" size -3 ljust at xc, y1
\&	line from (xc,y1) to (xc,y2)
\&	line from (xl,y2) to (xh,y2)
\&	line from (xl,y3) to (xh,y3)
\&	line from (xl,y4) to (xh,y4)
\&	line from (xl,y2) to (xl,y4)
\&	line from (xh,y2) to (xh,y4)
\&	line from (xc,y4) to (xc,y5)
\&	bullet at xc,y5
\&	"  $8" ljust size -3  at (xc,y5)
\&}
\&boxwidth = .3
\&box(1, .3, 2.0, 4.6, 11.2,20.3, Florida, Alaska)
\&box(3,.2, 3.7, 6.5, 9.5, 19.9, Ilhanova, Guallatiri)
\&.G2
.ft
.DE
.KE
.KS
.EQ
delim $$
.EN
.G1
frame invis ht 4 wid 3 bot solid
ticks off
coord x .5, 3.5 y 0,25
define Ht { "- $1,000 -" size -3 at 2, $1 }
Ht(5); Ht(10); Ht(15); Ht(20);
"Highest Point" "in 50 States" at 1,23
"Heights of" "219 Volcanos" at 3,23
"Feet" at 2,21.5; arrow from 2,22.5 to 2,24
define box {
	xc = $1; xl = xc - boxwidth/2; xh = xc+boxwidth/2
	y1 = $2; y2 = $3; y3 = $4; y4= $5; y5 = $6
	bullet at xc,y1
	"  $7" size -3 ljust at xc, y1
	line from (xc,y1) to (xc,y2)
	line from (xl,y2) to (xh,y2)
	line from (xl,y3) to (xh,y3)
	line from (xl,y4) to (xh,y4)
	line from (xl,y2) to (xl,y4)
	line from (xh,y2) to (xh,y4)
	line from (xc,y4) to (xc,y5)
	bullet at xc,y5
	"  $8" ljust size -3  at (xc,y5)
}
boxwidth = .3
box(1, .3, 2.0, 4.6, 11.2,20.3, Florida, Alaska)
box(3,.2, 3.7, 6.5, 9.5, 19.9, Ilhanova, Guallatiri)
.G2
.KE
.KS
.PP
A large but boring graph.  No data, but it does show off passing size
parameters to 
.I pic ,
and using non-brace macro delimiters.
.EQ
delim off
.EN
.DS
.ft CW
\&.ps 14
\&.vs 18
\&.G1 4
\&frame ht 2 wid 2
\&label left "Response Variable" left .2
\&label bot "Factor Variable" down .1
\&line from 0,0 to 1,1
\&line dotted from .5,0 to .5,1
\&define blob X "\\v'.1m'\\(bu\\v'-.1m'" X
\&blob at 0,.5; blob at .5, .5; blob at 1,.5
\&.G2
\&.ps 10
\&.vs 12
.ft
.DE
.EQ
delim $$
.EN
.ps 14
.vs 18
.G1 4
frame ht 2 wid 2
label left "Response Variable" left .2
label bot "Factor Variable" down .1
line from 0,0 to 1,1
line dotted from .5,0 to .5,1
define blob X "\v'.1m'\(bu\v'-.1m'" X
blob at 0,.5; blob at .5, .5; blob at 1,.5
.G2
.ps 10
.vs 12
.KE
.KS
.PP
This displays all the macros defined in 
.CW grap.defines .
No data.
.EQ
delim off
.EN
.DS
.ft CW
\&.G1
\&define box {"\\s-2\\f(ZD\\N'110'\\fP\\s0"}
\&frame ht 2 wid 2
\&coord x 0,3 y 0,6
\&ticks off
\&ticks left in left .1 from 1 to 5
\&ticks right in from 1 to 5 ""
\&ticks bot in down .1 from 1 to 2
\&ticks top in from 1 to 2 ""
\&bullet at 1,1
\&plus at 1,2
\&box at 1,3
\&star at 1,4
\&dot at 1,5
\&times at 2,1
\&htick at 2,2
\&vtick at 2,3
\&square at 2,4
\&delta at 2,5
\&.G2
.ft
.DE
.EQ
delim $$
.EN
.G1
define box {"\s-2\f(ZD\N'110'\fP\s0"}
frame ht 2 wid 2
coord x 0,3 y 0,6
ticks off
ticks left in left .1 from 1 to 5
ticks right in from 1 to 5 ""
ticks bot in down .1 from 1 to 2
ticks top in from 1 to 2 ""
bullet at 1,1
plus at 1,2
box at 1,3
star at 1,4
dot at 1,5
times at 2,1
htick at 2,2
vtick at 2,3
square at 2,4
delta at 2,5
.G2
.KE
.KS
.PP
We saw this graph earlier using line drawing commands.  This version
uses the 
.CW bar
extension.  Bars are centered, so the 0.5 unit fudge factor is used.
If I were graphing this from scratch, I would rewrite the 
.I awk
script to place the bars correctly.
.EQ
delim off
.EN
.DS
.ft CW
\&.G1
\&frame invis bot solid
\&label bot "Populations (in Millions) of the 50 States"
\&label left "Number of States" left .1
\&ticks bot out from 0 to 35 by 5
\&coord x 0, 35 y 0, 13
\&copy "states2.d" thru {
\&	bar up $1+0.5 ht $2 fill 0.125
\&}
\&.G2
.ft
.DE
.EQ
delim $$
.EN
.G1
frame invis bot solid
label bot "Populations (in Millions) of the 50 States"
label left "Number of States" left .1
ticks bot out from 0 to 35 by 5
coord x 0, 35 y 0, 13
copy "states2.d" thru {
	bar up $1+0.5 ht $2 fill 0.125
}
.G2
.KE
.KS
.PP
The same graph with bars extending in the x direction.
.EQ
delim off
.EN
.DS
.ft CW
\&.G1
\&frame invis bot solid
\&label left "Populations (in Millions) of the 50 States"
\&label bot "Number of States"
\&ticks left out from 0 to 35 by 5
\&coord x 0, 13  y -0, 35 
\&copy "states2.d" thru {
\&	bar right $1+0.5 ht $2 fill 0.125
\&}
\&.G2
.ft
.DE
.EQ
delim $$
.EN
.G1
frame invis bot solid
label left "Populations (in Millions) of the 50 States"
label bot "Number of States"
ticks left out from 0 to 35 by 5
coord x 0, 13  y 0, 35 
copy "states2.d" thru {
	bar right $1+0.5 ht $2 fill 0.125
}
.G2
.KE
.KS
.PP
Demonstration of negative bar heights.
.EQ
delim off
.EN
.DS
.ft CW
\&.G1
\&frame invis bot solid
\&copy until "DONE" thru {
\&	bar up $1 ht $2
\&}
\&1 -2
\&2 -1
\&3 0
\&4 1
\&5 2
\&DONE
\&.G2
.ft
.DE
.EQ
delim $$
.EN
.G1
frame invis bot solid
copy until "DONE" thru {
	bar up $1 ht $2
}
1 -2
2 -1
3 0
4 1
5 2
DONE
.G2
.KE
.KS
.PP
A display of two timing measurements and the components thereof.  The
data is fabricated, I just wanted to show the format, including both
formats of 
.CW bar
statement.
.EQ
delim off
.EN
.DS
.ft CW
\&.G1
\&frame invis bot solid left solid
\&ticks bottom off
\&grid bottom invis at 1 "OS 1", 2 "OS2"
\&coord y 0, 10
\&copy until "DONE" thru {
\&	bar up $1 ht $2 wid 0.5 base $3 fill $4
\&}
\&1 3 0 0.25
\&1 1 3 0.5
\&1 4 4 0.9
\&2 1 0 0.25
\&2 4 1 0.5
\&2 2 5 0.9
\&DONE
\&copy until "DONE" thru {
\&	bar 1.5,$1, 1.75, $1+0.2 fill $2
\&	$3 size -2 ljust at 1.8,$1+0.1
\&}
\&9 0.25 "Copying"
\&8.5 0.5 "Initialization"
\&8  0.9 "Checksum"
\&DONE
\&bar 1.45,9.35, 2.25, 7.85 dashed
\&.G2
.ft
.DE
.EQ
delim $$
.EN
.G1
frame invis bot solid left solid
ticks bottom off
grid bottom invis at 1 "OS 1", 2 "OS2"
coord y 0, 10
copy until "DONE" thru {
	bar up $1 ht $2 wid 0.5 base $3 fill $4
}
1 3 0 0.25
1 1 3 0.5
1 4 4 0.9
2 1 0 0.25
2 4 1 0.5
2 2 5 0.9
DONE
copy until "DONE" thru {
	bar 1.5,$1, 1.75, $1+0.2 fill $2
	$3 size -2 ljust at 1.8,$1+0.1
}
9 0.25 "Copying"
8.5 0.5 "Initialization"
8  0.9 "Checksum"
DONE
bar 1.45,9.35, 2.25, 7.85 dashed
.G2
.KE
.KS
.PP
This shows the new filling and linestyle capabilities of the 
.CW circle
and 
.CW bar
commands
.EQ
delim off
.EN
.DS
.ft CW
\&.G1
\&bar (1,1), (0,0) fill 0.25
\&circle at 0.5,0.5 rad 0.5 dashed 0.05 fill 0.5
\&.G2
.ft
.DE
.G1
bar (1,1), (0,0) fill 0.25
circle at 0.5,0.5 rad 0.5 dashed 0.05 fill 0.5
.G2
.KE
.KS
This is a more complex example of nested macros from Anindo Banerjea's
thesis.  This originally caught errors in the use of multiple
positioning commands for labels.  I don't know what the data are, but
a full explanation is in his Ph.D thesis.  In-line data 
and the groff for the caption are elided.  Two lines present in the
real graph are missing from this one.
.DS
.ft CW
.ps 8
.vs 10
\&.ds ** \\v'+.2m'\\fB*\\fP\\v'-.2m'
\&.vs 10
\&.G1
\&define myplot % # (symbol)
\&next linename at $1,$2
\&symb at $1,$2
\&%
\&graph A
\&frame invis ht 1.667 wid 2.0 left solid bot solid
\&coord y 0,70
\&label bot "delay (ms)" "\\fIi)\\fP" down 0.3
\&label left "load" unaligned "index" up .9
\&label right "Xmin =  2: \\(bu" unaligned ljust size -3 "Xmin =  4:\\(sq" \\
\&	"Xmin =  8:\\(ci" "Xmin = 16: \\*(**" left 1.4 up 0.5
\&draw a solid
\&define symb % bullet %
\&define linename { a }
\&copy until "XXX" thru myplot 
\&50  42.000
\&...
\&XXX
\&draw b solid
\&define symb % square %
\&define linename { b }
\&copy until "XX1" thru myplot 
\&50  22.000
\&...
\&XX1
\&.G2
.ft
.ps 10
.vs 12
.DE
.ds ** \v'+.2m'\fB*\fP\v'-.2m'
.vs 10
.G1 2i
define myplot % # (symbol)
next linename at $1,$2
symb at $1,$2
%
graph A
frame invis ht 1.667 wid 2.0 left solid bot solid
coord y 0,70
label bot "delay (ms)" "\fIi)\fP" down 0.3
label left "load" unaligned "index" up .9
label right "Xmin =  2: \(bu" unaligned ljust size -3 "Xmin =  4:\(sq" \
	"Xmin =  8:\(ci" "Xmin = 16: \*(**" left 1.4 up 0.5
draw a solid
define symb % bullet %
define linename { a }
copy until "XXX" thru myplot 
50  42.000
60  41.800
70  41.400
80  40.000
90  39.000
100  37.800
110  36.400
120  33.000
130  31.000
140  28.800
150  26.400
160  21.000
170  18.000
180  14.800
190  11.400
200   4.000
210   4.000
220   4.000
XXX
draw b solid
define symb % square %
define linename { b }
copy until "XX1" thru myplot 
50  22.000
60  21.800
70  21.600
80  20.800
90  20.200
100  19.600
110  18.800
120  17.000
130  16.000
140  14.800
150  13.600
160  10.800
170   9.200
180   7.600
190   5.800
200   2.000
210   2.000
220   2.000
XX1
.G2
.LP
\fB Figure 1.\fP Queueing Delay index vs. other load indices: Graph
\fIi)\fP shows that the proposed load index is monotonically decreasing
as a function of delay if all other factors are constant. Graph
\fIii)\fP shows that it is linear in bandwidth and graph \fIiii)\fP
shows that it is linear in the path length of the route provided the
delay requirement per hop remains constant.
.vs 12
.KE
.KS
.PP
This graph is pretty brutal all around.  Nested macros and constructed
filenames produce a bar graph (some of the components separated by
dots in the included filenames were originally pathname components).
This source is also from Anindo Banerjea, and caught bugs related to
.CW if
and 
.CW for 
statements.  Anindo wrote this to display a graph for
his thesis, not to demonstrate perfect
.CW grap 
programming form.  His graphs are used with his permission, I've made
minor tweaks to his code to make them more pretty under this version
of 
.CW grap .
.DS
.ft CW
.ps 8
.vs 10
\&.G1
\&define write_name % #(code,X,Y)
\&  if ($1 == 1) then {
\&    "\\s-2G\\s+2" above at $2,$3 
\&  }
\&  if ($1 == 2) then {
\&    "\\s-2H\\s+2" above at $2,$3
\&  }
\&  if ($1 == 3) then {
\&    "\\s-2L\\s+2" above at $2,$3
\&  }
\&  if ($1 == 4) then {
\&    "\\s-2I\\s+2" above at $2,$3
\&  }
\&  if ($1 == 5) then {
\&    "\\s-2R1\\s+2" above at $2,$3
\&  }
\&  if ($1 == 6) then {
\&    "\\s-2R2\\s+2" above at $2,$3
\&  }
\&  if ($1 == 7) then {
\&    "\\s-2R3\\s+2" above at $2,$3
\&  }
\&  if ($1 == 8) then {
\&    "\\s-2S\\s+2" above at $2,$3 
\&  }
\&%   
\&define dashedbar % #(X,Y)
\&  line from $1,0 to $1,$2 dashed
\&  line from $1,$2 to $1+9,$2 dashed
\&  line from $1+9,$2 to $1+9,0 dashed
\&%
\&define abar % #(X,Y)
\&  line from $1,0 to $1,$2
\&  line from $1,$2 to $1+9,$2
\&  line from $1+9,$2 to $1+9,0
\&%
\&define bar_succ % #(load,y,junk)
\&  abar(curx,$2)
\&  write_name(name,curx+5,$2)
\&  curx = curx + jump
\&  if (Maxy < $2) then { Maxy = $2 }
\&%
\&define bar_goodness % #(load,y,junk)
\&  abar(curx,$3-100)
\&  write_name(name,curx+5,$3-100)
\&  curx = curx + jump
\&  if (Maxy < ($3-100) ) then { Maxy = $3-100 }
\&%
\&define bar_avmax % #(load,average,max)
\&  abar(curx,$2)
\&  dashedbar(curx,$3)
\&  write_name(name,curx+5,$3)
\&  curx = curx+jump
\&  if (Maxy < $3) then { Maxy = $3 }
\&%
\&define bar_set % #(filename,jump,startX,name,function)
\&  jump = $2
\&  curx = $3
\&  name = $4
\&  copy $1 thru bar_$5
\&%
\&define setload % #(load, junk, junk
\&  ticks bot in 0.0 at ((2*count+1)*jump-gap/2)/2 "$1"
\&  count = count + 1
\&%
\&define mkgraphTiming % #(Timing,Name,file,function,number,ylabel,dir,toplable)
\&  Maxy = 0.0
\&  Nbars = 3
\&  start = 1
\&  gap = 15 
\&  jump = Nbars * 10 + gap
\&  bar_set("$7.Global.$1.$3.result",jump,start,1,$4)
\&  bar_set("$7.Hybrid.$1.$3.result",jump,start + 10,2,$4)
\&  bar_set("$7.Local.$1.$3.result",jump,start + 2*10,3,$4)
\&  line from 0,0 to jump*4-gap,0
\&  count = 0
\&  copy "$7.Local.$1.$3.result" through setload
\&  label top "\\fI$5)\\fP Timing = $2, $8" up .2
\&  label left $6 unaligned up 1.8 right .2
\&  label bot "load"  
\&  frame invis ht 3 wid 3 left solid bot solid
\&%
\&graph A
\&   mkgraphTiming(Random1500,Random-1500 ms,succ,succ,i,"SR (%)",\\
\&	result.SQ_MESH.Fail1.S3.R0,Square mesh)
\&.G2
.ft
.ps 10
.vs 12
.DE
.G1 2.5i
define write_name % #(code,X,Y)
  if ($1 == 1) then {
    "\s-2G\s+2" above at $2,$3 
  }
  if ($1 == 2) then {
    "\s-2H\s+2" above at $2,$3
  }
  if ($1 == 3) then {
    "\s-2L\s+2" above at $2,$3
  }
  if ($1 == 4) then {
    "\s-2I\s+2" above at $2,$3
  }
  if ($1 == 5) then {
    "\s-2R1\s+2" above at $2,$3
  }
  if ($1 == 6) then {
    "\s-2R2\s+2" above at $2,$3
  }
  if ($1 == 7) then {
    "\s-2R3\s+2" above at $2,$3
  }
  if ($1 == 8) then {
    "\s-2S\s+2" above at $2,$3 
  }
%   
define dashedbar % #(X,Y)
  line from $1,0 to $1,$2 dashed
  line from $1,$2 to $1+9,$2 dashed
  line from $1+9,$2 to $1+9,0 dashed
%
define abar % #(X,Y)
  line from $1,0 to $1,$2
  line from $1,$2 to $1+9,$2
  line from $1+9,$2 to $1+9,0
%
define bar_succ % #(load,y,junk)
  abar(curx,$2)
  write_name(name,curx+5,$2)
  curx = curx + jump
  if (Maxy < $2) then { Maxy = $2 }
%
define bar_goodness % #(load,y,junk)
  abar(curx,$3-100)
  write_name(name,curx+5,$3-100)
  curx = curx + jump
  if (Maxy < ($3-100) ) then { Maxy = $3-100 }
%
define bar_avmax % #(load,average,max)
  abar(curx,$2)
  dashedbar(curx,$3)
  write_name(name,curx+5,$3)
  curx = curx+jump
  if (Maxy < $3) then { Maxy = $3 }
%
define bar_set % #(filename,jump,startX,name,function)
  jump = $2
  curx = $3
  name = $4
  copy $1 thru bar_$5
%
define setload % #(load, junk, junk
  ticks bot in 0.0 at ((2*count+1)*jump-gap/2)/2 "$1"
  count = count + 1
%
define mkgraphTiming % #(Timing,Name,file,function,number,ylabel,dir,toplable)
  Maxy = 0.0
  Nbars = 3
  start = 1
  gap = 15 
  jump = Nbars * 10 + gap
  bar_set("$7.Global.$1.$3.result",jump,start,1,$4)
  bar_set("$7.Hybrid.$1.$3.result",jump,start + 10,2,$4)
  bar_set("$7.Local.$1.$3.result",jump,start + 2*10,3,$4)
  line from 0,0 to jump*4-gap,0
  count = 0
  copy "$7.Local.$1.$3.result" through setload
  label top "\fI$5)\fP Timing = $2, $8" up .2
  label left $6 unaligned up 1.8 right .2
  label bot "load"  
  frame invis ht 3 wid 3 left solid bot solid
%
graph A
   mkgraphTiming(Random1500,Random-1500 ms,succ,succ,i,"SR (%)",result.SQ_MESH.Fail1.S3.R0,Square mesh)
.G2
.KE
.KS
.PP
This is a graph donated by Bruce Lilly, after it demonstrated a couple 
.CW grap
bugs and incompatibilities with DWB
.CW grap .
But mostly I include it because it's a cool timing diagram, although I
have no idea for what.  I shrunk it for this example, so this version
is a little more cramped than his.  Remove the 4 that follows the .G1
to see the diagram in its full glory.
.DS
.ft CW
.ps 8
.vs 10
\&.G1 4
\&.ps 14
\&frame ht 5 wid 6 top invis right invis left invis bot invis
\&ticks off
\&coord x -21, 21 y 0, 70
\&line dashed from (0,0) to (0,68)
\&line dotted from (-11,0) to (-11,70)
\&line dotted from (11,0) to (11,70)
\&"clock" rjust at -21, 3.5
\&"data" rjust at -21, 35
\&"timing reference" below at 0, -1
\&"recovery window" at 0, 70
\&arrow from (-6,70) to (-10,70)
\&arrow from (6,70) to (10,70)
\&"``perfect'' data" at 0, 13.5
\&"jitter" at 0, 23.5
\&"timing offset" at 0, 38.3
\&"timing offset + jitter" at 0, 58.3
\&.\\"	clock
\&draw solid
\&[inline data elided]
\&.\\"	perfect data
\&new solid
\&[inline data elided]
\&new solid
\&[inline data elided]
\&.\\"	data with jitter +-3 ns
\&new solid
\&[inline data elided]
\&new solid
\&[inline data elided]
\&.\\"	+3 ns
\&new dashed
\&[inline data elided]
\&new dashed
\&[inline data elided]
\&.\\"	-3 ns
\&new dashed
\&[inline data elided]
\&new dashed
\&[inline data elided]
\&.\\"	timing offset +3 ns
\&new solid
\&[inline data elided]
\&new solid
\&[inline data elided]
\&.\\"	timing offset -3 ns
\&new solid
\&[inline data elided]
\&new solid
\&[inline data elided]
\&.\\"	+3 ns timing offset +-3 ns jitter
\&.\\"	+3 ns timing offset
\&new solid
\&[inline data elided]
\&new solid
\&[inline data elided]
\&.\\"	-3 ns jitter around +3 ns timing offset
\&new dashed
\&[inline data elided]
\&new dashed
\&[inline data elided]
\&.\\"	+3 ns jitter around +3 ns timing offset
\&new dashed
\&[inline data elided]
\&new dashed
\&[inline data elided]
\&.\\"	-3 ns timing offset +-3 ns jitter
\&.\\"	-3 ns timing offset
\&new solid
\&[inline data elided]
\&new solid
\&[inline data elided]
\&.\\"	-3 ns jitter around -3 ns timing offset
\&new dashed
\&[inline data elided]
\&new dashed
\&[inline data elided]
\&.\\"	+3 ns jitter around -3 ns timing offset
\&new dashed
\&[inline data elided]
\&new dashed
\&[inline data elided]
\&.ps
\&.G2
.ft
.DE
.G1 4
.ps 14
frame ht 5 wid 6 top invis right invis left invis bot invis
ticks off
coord x -21, 21 y 0, 70
line dashed from (0,0) to (0,68)
line dotted from (-11,0) to (-11,70)
line dotted from (11,0) to (11,70)
"clock" rjust at -21, 3.5
"data" rjust at -21, 35
"timing reference" below at 0, -1
"recovery window" at 0, 70
arrow from (-6,70) to (-10,70)
arrow from (6,70) to (10,70)
"``perfect'' data" at 0, 13.5
"jitter" at 0, 23.5
"timing offset" at 0, 38.3
"timing offset + jitter" at 0, 58.3
.\"	clock
draw solid
-21, 7
-16, 0
-2.5, 0
2.5, 7
16, 7
21, 0
.\"	perfect data
new solid
-21, 17
-16, 10
16, 10
21, 17
new solid
-21, 10
-16, 17
16, 17
21, 10
.\"	data with jitter +-3 ns
new solid
-21, 27
-16, 20
16, 20
21, 27
new solid
-21, 20
-16, 27
16, 27
21, 20
.\"	+3 ns
new dashed
-21, 27
-18, 27
-13, 20
19, 20
21, 22.8
new dashed
-21, 20
-18, 20
-13, 27
19, 27
21, 24.2
.\"	-3 ns
new dashed
-21, 22.8
-19, 20
13, 20
18, 27
21, 27
new dashed
-21, 24.2
-19, 27
13, 27
18, 20
21, 20
.\"	timing offset +3 ns
new solid
-21, 37
-18, 37
-13, 30
19, 30
21, 32.8
new solid
-21, 30
-18, 30
-13, 37
19, 37
21, 34.2
.\"	timing offset -3 ns
new solid
-21, 44.2
-19, 47
13, 47
18, 40
21, 40
new solid
-21, 42.8
-19, 40
13, 40
18, 47
21, 47
.\"	+3 ns timing offset +-3 ns jitter
.\"	+3 ns timing offset
new solid
-21, 57
-18, 57
-13, 50
19, 50
21, 52.8
new solid
-21, 50
-18, 50
-13, 57
19, 57
21, 54.2
.\"	-3 ns jitter around +3 ns timing offset
new dashed
-21, 57
-15, 57
-10, 50
21, 50
new dashed
-21, 50
-15, 50
-10, 57
21, 57
.\"	+3 ns jitter around +3 ns timing offset
new dashed
-21, 57
-16, 50
16, 50
21, 57
new dashed
-21, 50
-16, 57
16, 57
21, 50
.\"	-3 ns timing offset +-3 ns jitter
.\"	-3 ns timing offset
new solid
-21, 64.2
-19, 67
13, 67
18, 60
21, 60
new solid
-21, 62.8
-19, 60
13, 60
18, 67
21, 67
.\"	-3 ns jitter around -3 ns timing offset
new dashed
-21, 67
10, 67
15, 60
21, 60
new dashed
-21, 60
10, 60
15, 67
21, 67
.\"	+3 ns jitter around -3 ns timing offset
new dashed
-21, 60
-16, 67
16, 67
21, 60
new dashed
-21, 67
-16, 60
16, 60
21, 67
.ps
.G2
.\" "
.KE
.KS
Bruce Lilly also suggests this example.  He says:
.QP
I've attached a small data file and simple grap specification which shows
one way to handle missing data (and perhaps also how to ignore a column
header row in a data file). The data is annual US bicyclist fatalities as
published by the National Highway Transportation Safety Administration
.I http://www.nhtsa.dot.gov/people/ncsa/factshet.html ; (
the \*Qfact sheets\*U for
\*Qpedalcyclists\*U for 1998 and for 1993) and by the National Center for
Injury Prevention and Control
.I http://www.cdc.gov/ncipc/osp/us9693/mvpctr.htm ; (
change the numbers for
different years). CDC data hasn't yet been published for 1997 or 1998.
Don't ask me why two groups of bureaucrats in the US Federal Government
can't agree on the numbers.  The data is, of course, public information,
and there's no reason why you can't use the trivial grap
specification (though you might wish to embellish it).
.LP
I did embellish it by adding labels and a key.
.DS
.CW
\&.G1
\&label top "Bicycling Deaths by Year"
\&label left "Deaths" left 0.2
\&label bottom "Year"
\&copy "cy_fatal.d" through {
\&	# ignore missing data (zero or negative values 
\&	# used as placeholders). It also happens to ignore column
\&	# header rows in data.
\&	if $2 > 0 then {square at $1,$2 }
\&	if $3 > 0 then {bullet at $1,$3 }
\&}
\&square at 1993, 925
\&"NHTSA data" ljust at 1993.5, 925
\&bullet at 1993, 900
\&"CDC data" ljust at 1993.5, 900
\&line from 1992.5,940 to 1998,940
\&line from 1998,940 to 1998,890
\&line from 1998,890 to 1992.5, 890
\&line from 1992.5, 890 to 1992.5,940
\&.G2
.DE
.G1
label top "Bicycling Deaths by Year"
label left "Deaths" left 0.2
label bottom "Year"
copy "cy_fatal.d" through {
	# ignore missing data (zero or negative values
	# used as placeholders).  It also happens to ignore column
	# header rows in data.
	if $2 > 0 then {square at $1,$2 }
	if $3 > 0 then {bullet at $1,$3 }
}
square at 1993, 925
"NHTSA data" ljust at 1993.5, 925
bullet at 1993, 900
"CDC data" ljust at 1993.5, 900
line from 1992.5,940 to 1998,940
line from 1998,940 to 1998,890
line from 1998,890 to 1992.5, 890
line from 1992.5, 890 to 1992.5,940
.G2
.KE
.KS
This example shows off the new automatic tick generation for named
coordinate systems.  It is a re-plot of earlier data.  The automatic
ticks do not look great here because they are generated on a
logarithmic axis.  Still, it means that the graph can be generated
without constants in the grap code.
.DS
.CW
\&.G1
\&define square {"\\s-2\\(sq\\s0"}
\&frame ht 3 wid 3.5
\&label left "Population in Millions (Plotted as \(bu)"
\&label bot "Rank in Population"
\&label right "Representatives (Plotted as \(sq)"
\&coord pop log y
\&coord rep log y
\&ticks left out auto pop
\&ticks bot out auto pop
\&ticks right out auto rep
\&thisrank = 50
\&copy "states.d" thru {
\&	bullet at pop thisrank,$3/1e6
\&	square at rep thisrank,$2
\&	thisrank = thisrank -1
\&}
\&.G2
.DE
.G1
define square {"\s-2\(sq\s0"}
frame ht 3 wid 3.5
label left "Population in Millions (Plotted as \(bu)"
label bot "Rank in Population"
label right "Representatives (Plotted as \(sq)"
coord pop log y
coord rep log y
ticks left out auto pop
ticks bot out auto pop
ticks right out auto rep
thisrank = 50
copy "states.d" thru {
	bullet at pop thisrank,$3/1e6
	square at rep thisrank,$2
	thisrank = thisrank -1
}
.G2
.KE
.KS
.PP
This is a demonstration of the new line clipping.  The right graph is
a detail of the left, created by simply respecifying the coordinate
limits.  (The region plotted in the right graph is the dotted
rectangle in the left.)  Note that the data is clipped leaving the
area plotted and returning.  The data is the 400 Meter Run Olympic
data from before.
.EQ
delim off
.EN
.DS
.ft CW
\&graph Main
\&frame invis ht 2 wid 2.5 left solid bot solid
\&label left "Time (in seconds)"
\&label bot "Olympic 400 Meter Run: Winning Times" right 1.75
\&coord x 1894, 1994 y 42, 56
\&ticks left out at 44 "44", 46, 48 "48", 50, 52 "52", 54
\&ticks bot in from 1900 to 1980 by 20
\&draw solid
\&copy "400mpairs.d"
\&bar (1908,46), (1940,49) dashed
\&# detail graph
\&graph Detail with .w at Main.Frame.e +(0.1,0)
\&frame dashed ht 2 wid 2.5 right solid bot solid
\&label right "Time (in seconds)" 
\&ticks left off
\&ticks right on
\&ticks bot in
\&draw solid
\&copy "400mpairs.d"
\&coord x 1908,1942 y 45,49
.ft
.DE
.EQ
delim $$
.EN
.G1
graph Main
frame invis ht 2 wid 2.5 left solid bot solid
label left "Time (in seconds)"
label bot "Olympic 400 Meter Run: Winning Times" right 1.75
coord x 1894, 1994 y 42, 56
ticks left out at 44 "44", 46, 48 "48", 50, 52 "52", 54
ticks bot in from 1900 to 1980 by 20
draw solid
copy "400mpairs.d"
bar (1908,46), (1940,49) dashed
# detail graph
graph Detail with .w at Main.Frame.e +(0.1,0)
frame dashed ht 2 wid 2.5 right solid bot solid
label right "Time (in seconds)" 
ticks left off
ticks right on
ticks bot in
draw solid
copy "400mpairs.d"
coord x 1908,1942 y 45,49
.G2
.KE
.KS
.PP
Revisiting the boy heights example to demonstrate some other 
.CW grap
features.  New to this version is the ability to use x and y directly
as variable names anywhere but a 
.CW coord
statement.  Fixed as of release
1.10 is the ability to start a new line of the named style (or the
default if no name is given) using the 
.CW new 
statement.  The variable 
.CW y
is directly used in the computation of the regression, and each dashed
error bar is drawn using the conf line style.  Otherwise this is the
earlier graph.
.EQ
delim off
.EN
.DS
.ft CW
\&.G1
\&label left "Heights in Feet"
\&label bot "Heights of Boys in the US Ages 2-18"
\&cmpft = 12
\&minx = 1e12; maxx = -1e12
\&n = sigx = sigx2 = sigy = sigxy = 0;
\&draw conf dashed
\&copy "boyhts.d" thru {
\&	new conf
\&	next conf at $1, $2/cmpft
\&	next conf at $1, $4/cmpft
\&	y = $3 / cmpft
\&	bullet at $1, y
\&	n = n+1
\&	sigx = sigx + $1; sigx2 = sigx2 + $1 * $1
\&	sigy = sigy + y; sigxy = sigxy + $1*y
\&	minx = min(minx,$1); maxx = max(maxx,$1);
\&}
\&slope = ( n*sigxy - sigx* sigy) / (n*sigx2 - sigx * sigx)
\&inter = ( sigy - slope * sigx) / n
\&line from minx, slope * minx+inter to maxx, slope * maxx + inter
\&.G2
.ft
.DE
.EQ
delim $$
.EN
.G1
label left "Heights in Feet"
label bot "Heights of Boys in the US Ages 2-18"
cmpft = 12
minx = 1e12; maxx = -1e12
n = sigx = sigx2 = sigy = sigxy = 0;
draw conf dashed
copy "boyhts.d" thru {
	new conf
	next conf at $1, $2/cmpft
	next conf at $1, $4/cmpft
	y = $3 / cmpft
	bullet at $1, y
	n = n+1
	sigx = sigx + $1; sigx2 = sigx2 + $1 * $1
	sigy = sigy + y; sigxy = sigxy + $1*y
	minx = min(minx,$1); maxx = max(maxx,$1);
}
slope = ( n*sigxy - sigx* sigy) / (n*sigx2 - sigx * sigx)
inter = ( sigy - slope * sigx) / n
line from minx, slope * minx+inter to maxx, slope * maxx + inter
.G2
.KE
.KS
.PP
Some fun with embedded pic and troff to show that they work.  The
plotting points are made by a troff font change to Helvetica, drawing
an \*Qx\*U in grap, then a pic box around it, a second troff font
change and another grap label.  This example will almost certainly fail
under TeX.
.EQ
delim off
.EN
.DS
.ft CW
\&.G1
\&coord x 5,35 y 5, 35
\&ticks off
\&copy until "END" thru {
\&.	ft H
\&	"x" at $1, $2
\&	pic box ht 0.1 wid 0.1 at Here
\&.	ft R
\&	"" "$3" below at $1, $2
\&}
\&10 10 here's
\&20 20 some
\&30 30 pic/troff
\&END
\&.G2
.DE
.EQ
delim $$
.EN
.ft
.G1
coord x 5,35 y 5, 35
ticks off
copy until "END" thru {
.	ft H
	"x" at $1, $2
	pic box ht 0.1 wid 0.1 at Here
.	ft R
	"" "$3" below at $1, $2
}
10 10 here's
20 20 some
30 30 pic/troff
END
.G2
.KE
.KS
.PP
.CW grap
is now 
.I much 
more context sensitive in how it picks out keywords.  There are still
some places where it will resolutely not allow variables with keyword
names, but it's enormously better about it.  Here's a short somewhat
pathological example.  I couldn't decide which for loop was less
readable, so I used both.
.EQ
delim off
.EN
.DS
.ft CW
\&.G1
\&from=0
\&to = 10
\&ht =3
\&wid = 5
\&frame ht ht wid wid
\&for i from from to to do {
\&   delta at i, i
\&}
\&for j = from to to do {
\&   bullet at to - j, j
\&}
\&.G2
.ft
.DE
.EQ
delim $$
.EN
.G1
from=0
to = 10
ht =3
wid = 5
frame ht ht wid wid
for i from from to to do {
   delta at i, i
}
for j = from to to do {
   bullet at to - j, j
}
.G2
.KE
.bp
.KS
.PP
At the request of Bruce Lilly, coordinate spaces and variables now
have distinct name spaces, and those names spaces can (usually)
overlap both each other and keywords.  The result is that things like
this are legal.
.DS
.ft CW
\&.G1
\&from = 0
\&to = 10
\&new next dotted delta
\&for next from from to to do {
\&	next next at next next, next
\&}
\&ticks left on next
\&ticks bot on next
\&.G2
.ft
.DE
.G1
from = 0
to = 10
new next dotted delta
for next from from to to do {
	next next at next next, next
}
ticks left on next
ticks bot on next
.G2
.PP
I think we're now ready for the first obfuscated 
.CW grap
contest.  The following is a more readable version:
.DS
.ft CW
\&.G1
\&start = 0
\&finish = 10
\&new line_style dotted delta
\&coord coord_space
\&for i from start to finish do {
\&	next line_style at coord_space i, i
\&}
\&ticks left on coord_space
\&ticks bot on coord_space
\&.G2
.ft
.DE
.KE
.KS
One of the few things that one couldn't do under recent versions of 
.CW grap
was redefining keywords.  Now you can.  Here's an example that
redefines the bar keyword.  This also demonstrates the new undefine
keyword that restores the original bar semantics.
.DS
.ft CW
\&.G1
\&define bar { "_" } 
\&for i = 1 to 10 do {
\&	bar at i,i
\&}
\&undefine bar
\&bar up 5 ht 3
\&.G2
.G1
define bar { "_" } 
for i = 1 to 10 do {
	bar at i,i
}
undefine bar
bar up 5 ht 3
.G2
.DE
.KE
.KS
.PP
Bruce Lilly tells me that DWB 
.CW grap
defines some macros to make embedding pic code easier.  The macros are
named
.CW x_
.I coordname ,
.CW y_
.I coordname ,
and
.CW xy_
.I coordname .
The first 2 return a pic location corresponding to that x or y
coordinate in the given name space.  The third generates a pair of
coordinates in the given coordinate space.  The default coordinate
space is given by
.CW x_gg ,
.CW y_gg ,
and
.CW xy_gg .
If you define a coordinate space named gg, the macros will map one or
the other, but I don't know which.
.PP
DWB 
.CW grap
may use these as part of their implementation.  They're an extra
feature for compatibility here.
.PP
Here's a simple example of using these.  Note that the fors loop are 
pic for loops.  You don't have access to grap variables from pic.
.DS
.ft CW
\&.G1
\&coord test x 0, 10 y 0, 10
\&coord x 0, 20 y 0, 20
\&frame
\&ticks bot on test
\&ticks left on test 
\&pic for i = 0 to 9 do {
\&pic "x" at Frame.Origin + xy_test(i,i)
\&pic }
\&pic for i = 0 to 9 do {
\&pic "o" at Frame.Origin + xy_gg(1,i)
\&pic }
\&.G2
.G1
coord test x 0, 10 y 0, 10
coord x 0, 20 y 0, 20
frame
ticks bot on test
ticks left on test 
pic for i = 0 to 9 do {
pic "x" at Frame.Origin + xy_test(i,i)
pic }
pic for i = 0 to 9 do {
pic "o" at Frame.Origin + xy_gg(1,i)
pic }
.G2
.DE
.KE
.KS
.PP
A demo of 
.I grap 's
ability to directly manipulate label and plotting sizes.  The data is all in
the graph specification.
.EQ
delim off
.EN
.DS
.ft CW
\&.G1
\&frame ht 2 wid 2
\&coord x 0,100 y 0,100
\&grid bot dotted from 20 to 80 by 20 "%g" size +5
\&grid left dotted from 20 to 80 by 20 "%g" size -3
\&
\&"Text above" above at 50,50
\&"Text rjust   " rjust at 50,50
\&bullet at 80,90
\&vtick at 80,80
\&box at 80,70
\&times at 80,60
\&
\&circle at 50,50
\&circle at 50,80 radius .25
\&line dashed from 10,90 to 30,90
\&arrow from 10,70 to 30,90
\&
\&draw A solid
\&draw B dashed delta size 15
\&next A at 10,10
\&next B at 10,20
\&next A at 50,20
\&next A at 90,10
\&next B at 50,30
\&next B at 90,30
\&.G2
.ft
.DE
.EQ
delim $$
.EN
.G1
frame ht 2 wid 2
coord x 0,100 y 0,100
grid bot dotted from 20 to 80 by 20 "%g" size +5
grid left dotted from 20 to 80 by 20 "%g" size -3

"Text above" above at 50,50
"Text rjust   " rjust at 50,50
bullet at 80,90
vtick at 80,80
box at 80,70
times at 80,60

circle at 50,50
circle at 50,80 radius .25
line dashed from 10,90 to 30,90
arrow from 10,70 to 30,90

draw A solid
draw B dashed delta size 15
next A at 10,10
next B at 10,20
next A at 50,20
next A at 90,10
next B at 50,30
next B at 90,30
.G2
.KE
.bp
.EQ
delim $$
.EN
.PP
.KS
.PP
A gratuitous color graph.  Don't ever produce anything this ugly.  The
data is the 400m times used earlier.  There's a circle to show the color and
fillcolor attributes.  I've also added a thickness to one line and the circle.
.EQ
delim off
.EN
.DS
.ft CW
\&.G1
\&frame invis ht 2 wid 3 left solid color "blue" \\
\& 	bot solid color "orange"
\&label left "Time (in seconds)" left .15
\&label bot "Olympic 400 Meter Run: Winning Times"
\&coord x 1894, 1994 y 42, 56
\&ticks left out at 44 , 46 "", 48, 50 "", 52, 54 ""
\&ticks bot in from 1900 to 1980 by 20
\&grid bot ticks off  color "yellow" from 1900 to 1980 by 20
\&grid left ticks off  color "yellow" at 44, 46, 48, 50, 52, 54 
\&draw solid color "green" delta color "violet"
\&copy "400mpairs.d"
\&new color "red" thickness 2.5
\&copy "400wpairs.d"
\&"Women" size -3 at 1958,52
\&"Men" size -3 at 1910,47
\&circle at 1940, 52 rad 0.25 color "blue" fillcolor "red" \\
\&	fill 0.5 thickness 2
\&.G2
.ft
.DE
.EQ
delim $$
.EN
.G1
frame invis ht 2 wid 3 left solid color "blue" \
	bot solid color "orange"
label left "Time (in seconds)" left .15
label bot "Olympic 400 Meter Run: Winning Times"
coord x 1894, 1994 y 42, 56
ticks left out at 44 , 46 "", 48, 50 "", 52, 54 ""
ticks bot in from 1900 to 1980 by 20
grid bot ticks off  color "yellow" from 1900 to 1980 by 20
grid left ticks off  color "yellow" at 44, 46, 48, 50, 52, 54 
draw solid color "green" delta color "violet"
copy "400mpairs.d"
new color "red" thickness 2.5
copy "400wpairs.d"
"Women" size -3 at 1958,52
"Men" size -3 at 1910,47
circle at 1940, 52 rad 0.25 color "blue" fillcolor "red" \
	fill 0.5 thickness 2
.G2
.KE
.bp
.PP
Some people have tripped over 
.CW grap 's
fairly limited string manipulation capabilities.  Simply 
.CW grap
can only compare two quoted strings for equality.  Strings cannot be
assigned to variables.  Surprisingly, when combined with macros, that's
enough to do simple data selection, but not much more.  Here's an
example.
.KS
.EQ
delim off
.EN
.DS
.ft CW
\&.G1
\&copy until "END" thru {
\&    if ( "$1" == "yes" ) then {
\&        next at $2, $3
\&    }
\&}
\&yes 1 1
\&yes 2 2
\&no 3 3
\&yes 4 4
\&yes 5 5
\&END
\&.G2
.ft
.DE
.G1
copy until "END" thru {
if ( "$1" == "yes" ) then {
	next at $2, $3
}
}
yes 1 1
yes 2 2
no 3 3
yes 4 4
yes 5 5
END
.G2
.KE
.LP
Note that while data files can contain quotes, putting quotes in the
data file will 
.B not 
collect words into strings containing whitespace; 
.CW grap
splits lines of data files into words separated by whitespace.
.CW Grap 's 
macro substitution and line splitting are very literal and know nothing
about the language structure.  Overall, if you're planning anything more
complex than conditionals based on the contents of a single word
parameter to a macro call, do it outside 
.CW grap .
.CW Perl
and other scripting languages make complex text manipulations very easy.
Here's the same example with quotes in the file; notice the change in the
expression in the 
.CW if .
.KS
.EQ
delim off
.EN
.DS
.ft CW
\&.G1
\&copy until "END" thru {
\&    if ( $1 == "yes" ) then {
\&        next at $2, $3
\&    }
\&}
\&"yes" 1 1
\&"yes" 2 2
\&"no" 3 3
\&"yes" 4 4
\&"yes" 5 5
\&END
\&.G2
.ft
.DE
.G1
copy until "END" thru {
if ( $1 == "yes" ) then {
	next at $2, $3 
}
}
"yes" 1 1
"yes" 2 2
"no" 3 3
"yes" 4 4
"yes" 5 5
END
.G2
.KE
.bp
.LP
This demonstrates the 
.CW grap
features for manipulating dates by plotting a histogram of automobile
gas mileage.  The fields of the data are a date in yyymmdd format, an
odometer reading and the number of gallons on fill up.  The 
.CW strptime
function is used to convert the ad hoc date format into a plottable
number, and 
.CW strptime
is used to label ticks.
.KS
.EQ
delim off
.EN
.DS
.ft CW
\&.G1
\&max_mpg = last_date = last_miles = mn = mx = 0
\&copy until "END" thru { 
\&  # parse the date into seconds
\&  dt = strptime("%Y%m%d", "$1")
\&  if mn == 0 || dt < mn then { mn = dt }
\&  if mx == 0 || dt > mx then { mx = dt }
\&  if last_miles != 0 then { 
\&  	mpg = ($2 - last_miles)/$3
\&	if mpg > max_mpg then { max_mpg = mpg }
\&  	bar up (last_date + dt) / 2 ht mpg wid dt -last_date
\&  }
\&  last_miles = $2; last_date = dt 
\&}
\&20100623 34794 9.845
\&[...]
\&20111119 42802 9.539
\&END
\&for t from mn to mx by (mx - mn )/3 do {
\&	tick bot at t strftime("%Y-%m-%d", t)
\&}
\&label left "Miles per gallon"
\&label bot "Dates"
\&.G2
.ft
.DE
.G1
max_mpg = last_date = last_miles = mn = mx = 0
copy until "END" thru { 
  # parse the date into seconds
  dt = strptime("%Y%m%d", "$1")
  if mn == 0 || dt < mn then { mn = dt }
  if mx == 0 || dt > mx then { mx = dt }
  if last_miles != 0 then { 
  	mpg = ($2 - last_miles)/$3
	if mpg > max_mpg then { max_mpg = mpg }
  	bar up (last_date + dt) / 2 ht mpg wid dt -last_date
  }
  last_miles = $2; last_date = dt 
}
20100623 34794 9.845 
20100710 35066 9.804
20100728 35339 9.785
20100811 35623 10.026
20100826 35919 10.086
20100912 36192 9.536
20101001 36472 9.759
20101024 36737 9.848
20101113 37004 9.827
20101129 37257 9.806
20101218 37521 10.211
20110108 37774 9.868
20110122 38036 10.295
20110208 38293 9.693
20110220 38564 9.567
20110306 38817 9.577
20110325 39087 10.090
20110406 39350 9.893
20110422 39620 9.975
20110507 39913 10.089
20110522 40149 8.428
20110614 40411 10.007
20110702 40696 9.842
20110719 40982 10.219
20110806 41224 8.710
20110828 41510 9.775
20110917 41745 8.142
20111005 42018 9.841
20111019 42287 9.886
20111108 42545 9.732
20111119 42802 9.539
END
for t from mn to mx by (mx - mn )/3 do {
	tick bot at t strftime("%Y-%m-%d", t)
}
label left "Miles per gallon"
label bot "Dates"
.G2
.KE