I just added this Lindenmayer system generator to upcoming site Online Math Tools. Given the starting axiom and rewrite rules it draws pretty recursive curves.

You can draw icy patterns:

Icy Frost Fractal

And you can draw pentadendrites:

Pentadendrite Fractal (McWorter's Pentigree)

And you can draw islands:

Island L-System

And you can draw fractal trees:

Fractal tree

And you can draw many other things. Try it out and see you next time!