From ranchbots

%! Postscript utility for printing an encoder wheel % /inch {72 mul} def % #points/inch (don't change me) /size 0.5 inch def % radius of encoder wheel /segments 16 def % number of segments (black and white) /angle 360 segments div def /wedge { /radius exch def /angle_s exch def /angle_e exch def newpath 0 0 moveto 0 0 radius angle_s angle_e arc closepath } def gsave 1.0 inch 1.0 inch translate 0 1 segments { 360 segments div rotate angle 0 size wedge 2 mod 0 eq {1} {0} ifelse setgray fill } for grestore showpage