黄金の回転
PostScript 的にはこうですかね。
%!PS gsave 3 dict begin mark /clockwise? false def /a 4 def /phi 5 sqrt 1 add 2 div def 300 300 a a clockwise? not{neg}if 10{ 4 copy rectstroke 3 2 roll add exch dup phi mul exch clockwise?{neg}if 4 copy rectstroke pop dup 4 3 roll add 3 1 roll neg dup clockwise? not{neg}if }repeat showpage end cleartomark grestore