aUCBLogo Demos and Tests / rotmetal

to rotmetal
   WindowMode
   clearScreen
   hideTurtle
   PenUp
      right 180  forward 50  left 180
   PenDown
   setPenSize [.5 .5]
   setPenColor rgba 0 0 0 4/256
   for [i 1 255]
   [   for [j 1 255]
      [   setPenColor rgba i/512 (mod j*i 255)/512 j/512 4/256
         square 100
         forward 0.05
         right 0.01*i
      ]
      forward 25
      left 1
      updateGraph
      if Key? [stop]
   ]
   print [OK]
end

to diagonal size
   PenUp
   right 45
   forward size*sqrt 2
   right 135
   PenDown
end

to square size
   diagonal size/2
   repeat 4
   [   forward size
      right 90
   ]
   diagonal size/2
end