Want to change what it does? Try a lowercase letter, any lowercase letter. They are mostly toggles. If you press 'r', the result will probably not be peaceful and calm.
The bottom row of keys changes the shape that's being spun.
The lefthand side of the middle row controls drawing modes:'a' causes it to draw one layer and stop. 's' stops whatever's going on where it is. 'd' causes it to reinitialize some variables between layers. 'f' causes it to draw the next layer (if it's not stopped, but it's not drawing anything, either). 'g' clears the screen and puts up a new background without changing any parameters. 'h', like a mouse click, wipes everything over and generates mostly-new parameters. (Thus, to get previous modes of operation, you can press 'd' to get the constant variation, or 'a' to get draw one layer and stop.)
j flips it between reflections and pure rotations, k flips between simpler and more complex. l decreases the number of points (L increases it). q-t change color or lineweight. 'y' is hard to describe, but visibly different. 'u' changes the speed, 'i' the number of lines per layer, 'o' whether the lines are linearly or non-linearly scaled, and 'p' the qualities of the fill. Good luck with mnemonics.