%PS%
  % 60 lpi
60  15          %cyan
{abs exch abs 2 copy add 1 gt
  {1 sub dup mul exch 1 sub dup mul add 1 sub}
  {dup mul exch dup mul add 1 exch sub}
  ifelse}
60  75  2 index %magenta
60  0.  2 index %yellow
60  45. 2 index %black
setcolorscreen
/PE where {pop PE}if