Press the Green flag to draw a Wirth curve. Wait a few seconds to see more complex images.
The Wirth curve is another space-filling fractal. Depending on which pattern captures your attention, it might look like a graveyard full of crosses, or, if you focus on the spaces in between, you see lots of thick Xs. This curve is described in Jeffrey Ventrella's book "Brainfilling Curves - a Fractal Bestiary".
