aUCBLogo Demos and Tests / gearing

to gearing
   WindowMode
   clearScreen
   hideTurtle
   PenUp  left 90  forward 50  right 90  PenDown
   setPenSize [.5 .5]
   for [i 1 255]
   [    for [j 1 255]
      [   setPenColor rgba i/512 (mod j*i 255)/512 j/512 2/256
         square 400
         forward 20
         right 3.7*i
      ]
      forward 80
      left 17
      updateGraph
      if key? [stop]
   ]
   print [OK]
end

to square size
   repeat 4 [fd size  rt 90]
end