File:Triskelion-quasi-tessellation.svg
| Uploaded by | AnonMoos |
|---|---|
| Upload date | 2021-03-28T01:57:39Z |
| MIME type | image/svg+xml |
| Dimensions | 627 × 543 px |
| File size | 9.4 KB |
Summary
| Description | A quasi-tessellation of interlocked triskelions which are generated from mathematical Archimedean spirals. It is not a complete tessellation of the plane, since there are small uncovered concave triangular gaps between the triskelions. | ||
| Date | |||
| Source |
Converted from the following self-authored PostScript vector source code: %!
/archimtriple{
%%%%%%%%%%%%%%%%
% PostScript program to display an Archimedean spiral by approximating
% it with Bezier curves. Can display a triple spiral (three spirals
% rotated by 120 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 30 def % insert a curve point after this number of degrees
% /sweeps % number of 360 degree turnings to show
/triple 1 def % change to 0 to for non-triple inner spiral
%%% Procedures:
/pi 3.1415926535898 def/radians 57.295779513082 def
/sepwid sepwid pi div 2 div def
gsave centerx centery translate rotf rotate
/aspiral{/first 1 def
lower incrm sweeps 360 mul{8{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
0 eq phase 90 eq phase 270 eq or and{/slope 999999999 def}{/slope
sinth thcosth add costh thsinth sub div def}ifelse
sinth 0 gt sinth 0 eq costh -1 eq and or{/flag -1 def}{/flag 1
def}ifelse
/A exch def phase 0 eq phase 180 eq or {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}if
phase 120 eq phase 300 eq or{A 10 lt A 80 gt A 100 lt and
or{/flag flag neg def}if}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{0 0 moveto/prevbezx phase cos nextdist mul def/prevbezy
phase sin nextdist mul def/first 0 def}{first 1 eq{x y
moveto/first 0 def}{prevbezx prevbezy x 1 flag mul
normaliz div prevdist mul sub y slope flag mul normaliz
div prevdist mul sub x y curveto}ifelse
/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
%%% If different sweeps parameter for other spirals, define here:
/sweeps 1.26 def/phase 0 def aspiral
triple 0 ne{/phase 120 def aspiral
/phase 240 def aspiral} if grestore
%%%%%%%%%%%%%%%%
}def
306 396 translate
.5 dup scale
180 rotate
1 -1 scale
/lower 0 def
/centerx 0 def/centery 0 def/rotf 0 def
archimtriple
/centerx 0 def/centery 256.666667 def/rotf 0 def
archimtriple
/centerx -222.279854 def/centery -128.333333 def/rotf 0 def
archimtriple
/centerx 222.279854 def/centery -128.333333 def/rotf 0 def
archimtriple
/centerx 0 def/centery -256.666667 def/rotf 0 def
archimtriple
/centerx -222.279854 def/centery 128.333333 def/rotf 0 def
archimtriple
/centerx 222.279854 def/centery 128.333333 def/rotf 0 def
archimtriple
/centerx 0 def/centery 513.333333 def/rotf 0 def
archimtriple
/centerx 0 def/centery -513.333333 def/rotf 0 def
archimtriple
/centerx -444.559707 def/centery 0 def/rotf 0 def
archimtriple
/centerx 444.559707 def/centery 0 def/rotf 0 def
archimtriple
/centerx -444.559707 def/centery -256.6666670 def/rotf 0 def
archimtriple
/centerx 444.559707 def/centery 256.666667 def/rotf 0 def
archimtriple
/centerx -444.559707 def/centery 256.6666670 def/rotf 0 def
archimtriple
/centerx 444.559707 def/centery -256.666667 def/rotf 0 def
archimtriple
/centerx -222.279854 def/centery -385 def/rotf 0 def
archimtriple
/centerx 222.279854 def/centery -385 def/rotf 0 def
archimtriple
/centerx -222.279854 def/centery 385 def/rotf 0 def
archimtriple
/centerx 222.279854 def/centery 385 def/rotf 0 def
archimtriple
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%EOF |
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| Author | AnonMoos | ||
| Permission (Reusing this file) |
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| Other versions |
For another quasi-tessellation of triskelion shapes generated from Archimedean spirals, see File:Triskele-quasi-tesselation.svg . |