Another fun example of a computer generating mezmerizingly complex art from simple code is that as a kid, I wrote a Langton's Ant implementation in QBASIC on a DOS machine (don't remember the version). IIRC this was using Graphics Mode 1 (320 x 200 pixel framebuffer), and I used PSET and PRESET to draw white and black pixels. This so far sounds ordinary but:
The cool thing was that I forgot to write the bounds check to make sure the ant stayed inside the framebuffer! So the ant would happily trundle off-screen, encounter arbitrary bits that were in that memory, and would often eventually return back on the screen from a different location. Or sometimes (probably due to encountering zeros offscreen) it would run a lap around the edge of the screen and then veer back inward.