Just about any Forth Haiku would probably qualify. Here's a nice Mandelbrot set (not my code):

  : z^2 2dup z* ;
  : layer push push z^2 pop pop 2dup push push z+ pop pop ;
  : many layer layer layer layer layer layer layer layer layer layer ;
  : len dup * swap dup * + ;
  : mant y 0.7 - 3 * x 0.5 - 3 * many drop drop len dup 1 < * ;
  0 0 mant
  0.1 0.1 mant
  0.2 0.2 mant

(http://www.forthsalon.appspot.com/haiku-view/agpmb3J0aHNhbG9...)