input bbase;
 sunrules;	% use this to get boxes on the SUN screen

N.height = S.height = W.width = E.width = 18pt;
M.height = M.width = 24pt;

def noise=.1pt*(normaldeviate,normaldeviate) enddef;

pen largepen;
defaultpen:=pencircle scaled .4pt;
largepen:=pencircle scaled .6pt;

def horizline expr z =	% a horizontal line to the right of point z
	draw z+(.5pt,0)+noise .. z+(5.5pt,0)+noise; showit enddef;
def vertline expr z =	% a vertical line above point z
	draw z+(0,.5pt)+noise .. z+(0,5.5pt)+noise; showit enddef;

def moveright = xx:=xx+6pt enddef;	% move to next 6pt x 6pt square
def CR = xx:=x0; yy:=yy-6pt enddef;	% "carriage return"

def H =		% six horizontal lines
 for y := .5pt step pt until 6pt: horizline (xx,yy+y); endfor;
 moveright enddef;
def V =		% six vertical lines
 for x := .5pt step pt until 6pt: vertline (xx+x,yy); endfor;
 moveright enddef;
def C =		% superimpose a circle on the previous lines
 path p; p=(xx-5pt,yy+3pt)+noise .. (xx-3pt,yy+5pt)+noise ..
		(xx-1pt,yy+3pt)+noise .. (xx-3pt,yy+1pt)+noise .. cycle;
 cullit; erase p; cullit; showit; draw p withpen largepen; showit; enddef;

vardef char.N.M =
 xx:=x0:=3pt; yy:=15pt;
 H; V; H; V; CR;
 V; H; V; H; CR;
 H; V; H; V; enddef;

test N.M;

% the example file, continued:
vardef char.N.E =
 xx:=x0:=3pt; yy:=15pt;
 H; V; H; CR;
 V;H;C;V; CR;
 H; V; H; CR;
 V; H; V; enddef;

test N.E;

vardef char.N.W =
 xx:=x0:=-3pt; yy:=15pt;
 H; V; H; V; CR;
 V;H;C;V; H; CR;
 H; V; H; V; enddef;

test N.W;

vardef char.M.E =
 xx:=x0:=3pt; yy:=15pt;
 H; V; H; CR;
 V; H; V; CR;
 H; V; H; CR;
 V; H; V; enddef;

test M.E;

vardef char.M.W =
 xx:=x0:=-3pt; yy:=21pt;
 V; H; V; CR;
 H; V; H; CR;
 V; H; V; CR;
 H; V; H; enddef;

test M.W;

vardef char.S.M =
 xx:=x0:=-3pt; yy:=9pt;
 V; H; V; H; CR;
 H; V; H; V; CR;
 V; H; V; H; enddef;

test S.M;

vardef char.S.W =
 xx:=x0:=-3pt; yy:=15pt;
 V; H; V; CR;
 H; V; H; CR;
 V;H;C;V; CR;
 H; V; H; enddef;

test S.W;

vardef char.S.E =
 xx:=x0:=-3pt; yy:=9pt;
 V; H; V; H; CR;
 H; V;H;C;V; CR;
 V; H; V; H; enddef;

test S.E;
end