_set_fps(60)
::_::
  u=rnd(128)
  v=rnd(128)
  x=(u-64)/40
  y=(v-64)/50
  d=x*x+y*y
  z=sqrt(1-d)
  a=atan2(y,z)+t()/6
  b=atan2(x,z)+t()/6
  c=((a*b*a))%7+8
  if(d>1)c=0
  circfill(u,v,1,c)
goto _