Conway’s Game of Life for Curved Surfaces (Part 1) and Conway’s Game of Life for Curved Surfaces (Part 2) by Mikola Lysenko.
A generalization of John Conway’s original Game of Life on curved surfaces.
Definitely not for the faint of heart and will likely have you consulting old text books.
A simple game that even in its original version, unfolds into complexity. To say nothing of the extended version.
See Cellular automaton (history and applications).
I first saw this in a tweet from Math Update.