Inspired by the L-systems of Aristid Lindenmayer and a turtle-graphics program by Darius Bacon.
The text you type in this box is interpreted as a drawing program for a turtle. “f” draws a line forward, “r” turns 30° right, [xyz] defines (and invokes) a procedure called “x” defined as “yz” (which can be invoked elsewhere with simply “x”), and “@1.2” scales up all following drawing operations (until the end of the current procedure) by 1.2×. For example, t, x, s, h, q, k, w, m, f, d, ń, r, or g.