open window 640,512
window origin "cc"
f=pi/180
repeat
 setdispbuf cb
 cb=1-cb
 setdrawbuf cb
 clear window
 setrgb 1,r,g,b
 fill circle 0,0,200
 setrgb 1,255-r,255-g,255-b
 ang=sin(aa*f)*20
 aa=aa+5
 if aa=360 aa=0
 if aa=90 or aa=270 then
  r=ran(100)
  g=ran(100)
  b=ran(100)
 fi
 for a=0 to 350 step 10
  s1=sin((a+ang)*f)
  s2=sin((a-ang)*f)
  s3=sin((a-ang+10)*f)
  c1=cos((a+ang)*f)
  c2=cos((a-ang)*f)
  c3=cos((a-ang+10)*f)

  line s1*50,c1*50 to 0,0
  line s1*50,c1*50 to s2*100,c2*100
  line s1*150,c1*150 to s2*100,c2*100
  line s1*150,c1*150 to s2*200,c2*200
  line s2*200,c2*200 to s3*200,c3*200
 next a
until (1=2)



