Gray-Code-Scheiben-Generator

/mm {72 25.4 div mul} def

210 mm 2 div 297 mm 2 div translate %set origin to center of DinA4
1.00 1.00 scale
1 setlinewidth
0 0 20 0 360 arc  -20 -20 moveto  20 20 lineto  -20 20 moveto  20 -20 lineto  stroke

%14 setlinewidth
/rad 100 def %inner radius (+1/2 width)
/inc  10 def %width
/bit  3 def %number of bits
/num   3 def %internal variable
inc setlinewidth
0 0 rad 180 360 arc stroke /rad rad inc add def /bit bit 1 sub def %inner arc is a special case
bit{
  /win 90 num div def /sta win def /sto win 3 mul def
  num{0 0 rad sta sto arc stroke /sta sta win 4 mul add def /sto sto win 4 mul add def}repeat
  /num num 2 mul def/rad rad 15 add def}repeat

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