w,h = #.scrsize()
sfx = -2.5; sfy = -2*h/w; fs = 4/w
#.aaoff()
> y, 1...h
  > x, 1...w
    fx = sfx + x*fs; fy = sfy + y*fs
    #.drawpoint(x,y,color(fx,fy):3)
  <
<
color(x,y)=
  zr = x; zi = y; n = 0; maxn = 150
  > zr*zr+zi*zi<4 & n<maxn
    zrn = zr*zr-zi*zi+x; zin = 2*zr*zi+y
    zr = zrn; zi = zin; n += 1
  <
  ? n=maxn, <= 0,0,0
  <= #.hsv2rgb(n/maxn*360,1,1):3
.