aUCBLogo Demos and Tests / bifurkat

to bifurkat
;   norefresh   ;comment out for printing or saving
   clearScreen
   hideTurtle
;   enablePointSmooth
   sx=800
   sy=600
   c=Array sx
   repeat sx [c.repcount=2.8+(4-2.8)*repcount/sx]
   x=Array sx  repeat sx [x.repcount=0.5]
   _1=Array sx   repeat sx [_1.repcount=1]
   isx=Array iSeq 1 sx
   ix=isx*800/sx-400
   iter=500
   miniter=100
   repeat iter
   [   x=c*x*(_1-x)
      i=repcount
      color=HSBA 360*i/iter 1 1 1 ;0.2
      if repcount > miniter
      [   setPixelXY ix x*600-300 color
         updateGraph
      ]
      dispatchMessages
      if Key?
      [   if (rawASCII readChar)==WXK_ESCAPE
         [   break
         ]
      ]
   ]
   pr [OK]
end