color 555
proc tree x y deg n . .
   if n > 0
      linewidth n * 0.4
      move x y
      x += cos deg * n * 1.3 * (randomf + 0.5)
      y += sin deg * n * 1.3 * (randomf + 0.5)
      line x y
      tree x y deg - 20 n - 1
      tree x y deg + 20 n - 1
   .
.
timer 0
on timer
   clear
   tree 50 10 90 10
   timer 2
.
