setrgb 1,0,0,77
open window 640,512
label k
 setdispbuf bu:bu=1-bu:setdrawbuf bu
 m=m+.2
 for b=0 to 31
  y=cos((m+b*(sin(m/800)*20+38))/24)*256+256
  setrgb 2,(220+b)/3,0,0
  setrgb 3,b*3,0,b*8
  gtriangle 64,y-8 to 576,y-8 to 64,y+8
  gtriangle 56+y,0 to 56+y,576 to 72+y,0
  gtriangle 576,y+8 to 576,y-8 to 64,y+8
  gtriangle 72+y,576 to 56+y,576 to 72+y,0
 next b
goto k
