L-system fractal generator created for js1k contest.

The script executes given L-system code and generates fractals on the screen. This is the Hilbert curve:

iters: 7
angle: 90
start: "L"
L: "-Rf+LfL+fR-"
R: "+Lf−RfR−fL+"

iters if the number of iterations. angle is the turning angle in degrees. start is the initial axiom. Other lines are the rewrite rules. Supported operators are +− for turning, lowercase letters for drawing, and [] for push and pop.

For more examples, see here.