I think "quite interesting" is an understatement. This is the Game Of Life simulating the Game Of Life. I personally consider it to be one of the Great Wonders of software.
And it occurs to me, a blank sheet of paper qualifies as the Game Of Life simulating the Game Of Life.
https://adventofcode.com/2024/day/21
It really makes you think about this; interaction between levels in a simulation.
What are other Great Wonders of software?
- cryptography in general
- data compression
- a lot of DSP stuff is pretty magical in it's various applications - digital filtering, modulation/demodulation, recovery of weak signals in noisy environments, beam-forming etc
There's a lot of really amazing, largely mathematical, foundation work that we now tend to take for granted and without which we'd be back in the relative dark ages.