%!
/archimdouble{
%%%%%%%%%%%%%%%%
% PostScript program to display an Archimedean spiral by approximating
% it with Bezier curves. Can display a double spiral (two spirals
% rotated by 180 degrees with respect to each other).
%%% Parameters:
% centerx = horizontal coordinate of center of spiral
% centery = vertical coordinate of center of spiral
% rotf = degrees to rotate
/sepwid 110 def % width separating successive turnings of spiral
% (half this if double spiral is selected)
/incrm 15 def % insert a curve point after this number of degrees
/sweeps 3 def % number of 360 degree turnings to show
/double 1 def % change to 0 to display single spiral
/linew 13.75 def % increase number for thicker line
%%% Procedures:
/pi 3.1415926535898 def/radians 57.295779513082 def
/sepwid sepwid pi div 2 div def
gsave centerx centery translate rotf rotate linew setlinewidth
/aspiral{/prevbezy 0 def 0 0 moveto
0 incrm sweeps 360 mul{7{dup}repeat
phase add cos/costh exch def
phase add sin/sinth exch def
costh mul radians div/thcosth exch def
sinth mul radians div/thsinth exch def
thcosth sepwid mul/x exch def
thsinth sepwid mul/y exch def
/slope sinth thcosth add costh thsinth sub div def
sinth 0 gt sinth 0 eq costh -1 eq and or{/flag -1 def}{/flag 1
def}ifelse
/A exch def A 49.29348 lt A 180 gt A 196.273450852 lt and A 360
gt A 368.8301 lt and A 540 gt A 545.9907 lt and A 720 gt A
724.5217 lt and A 900 gt A 903.6281968 lt and or or or or
or{/flag flag neg def}if
incrm sub 3{dup}repeat phase add cos sepwid mul mul radians div
/prevx exch def phase add sin sepwid mul mul radians div
/prevy exch def
incrm add 3{dup}repeat phase add cos sepwid mul mul radians div
/nextx exch def phase add sin sepwid mul mul radians div
/nexty exch def
/prevdist x prevx sub dup mul y prevy sub dup mul add sqrt pi
div def
/nextdist x nextx sub dup mul y nexty sub dup mul add sqrt pi
div def
/normaliz slope slope mul 1 add sqrt def
0 eq{/prevbezx phase cos nextdist mul def}{prevbezx prevbezy
x 1 flag mul normaliz div prevdist mul sub y slope flag mul
normaliz div prevdist mul sub
x y curveto
/prevbezx x 1 flag mul normaliz div nextdist mul add def
/prevbezy y slope flag mul normaliz div nextdist mul add def}
ifelse}
for stroke}def
/phase 0 def aspiral
%%% If different sweeps parameter for second spiral, define here:
/sweeps 2.67 def
%%%
double 0 ne{/phase 180 def aspiral}if grestore
%%%%%%%%%%%%%%%%
}def
gsave
-9 0 translate
.4875 dup scale %%% decrease to .47 to fit on A4-size page
-2 rotate
/centerx 304 def/centery 550 def/rotf 0 def archimdouble
/centerx 927.334 def/centery 550 def/rotf 120 def archimdouble
/centerx 615.667 def/centery 1089.823 def/rotf 240 def archimdouble
grestore
showpage
%EOF
Author
AnonMoos
Licensing
Public domainPublic domainfalsefalse
I, the copyright holder of this work, release this work into the public domain. This applies worldwide. In some countries this may not be legally possible; if so: I grant anyone the right to use this work for any purpose, without any conditions, unless such conditions are required by law.
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Add a one-line explanation of what this file represents
== Summary == The Triple Spiral symbol, based on motifs found at the prehistoric site at
Newgrange, Ireland, and used as a neo-pagan or
Triple Goddess symbol. This version is made
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