lightning
Attempt at simulating a lightning-like figure (Lichtenberg figure). Works by keeping a field of potential electrons and randomly expanding into one. More frequently accessed branches thicken. Uses all sorts of haphazard optimisation to make it run, whatsoever. It uses a nice little trick so that a branches prevalence first grows rapidly, then slows - interpolation on the square root. Of course, features rainbow support.
Here is an example of it in action:
Here is a display of the "electron field":
Here is a short video of it in action.