Had to write postscript for "introduction into stackbased programming" at university.

We choose to make complex cylcoid "animations". We controlled the "animation"-speed by using helper routines that slowed down the postscript-viewer by painting nonsense white on white.

Downside of this was that it crashed printers and macOS Preview.

And the professor actually wanted us to write a parser or something else that could use a stack, but we were pretty satisfied with ourselves.