This is a version of the Chaos game method of generating fractals, but in 3 dimensions!
The main things to change is the shape being rendered (under the name "selected"), the c-value (to change spacing and scale), and the random number generation mode (randMode).
When in the simulation, the 'x' key will lock rotation to the x-axis, and the 'y' and 'z' keys will do the same for theirs. The 'a' key will free rotation again.
Pressing the 'l' key will show the x, y, and z-axes.