"Fractal enumeration". I'm taking this literally. Racket's graphics library can probably help you with that. It has some examples, too... In a fresh interaction with Racket, you can type the following:
[Unfortunately, at least for me, it seems you can't put those commands together--it seems that after startup, it displays each "turtle" as an orange triangle, and the "serp" (Sierpinski triangle) procedure creates a bunch of turtles, so you need to wait for the first turtle to get displayed before creating the rest, or else you'll just see a bunch of orange when they all get displayed.]