Tiny L-system Generator
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.