The Sound of Life
I have to say I'm pretty chuffed about this one. In a way it's a followup to Chip from the other week, but this one took a fair bit more wrangling to get to behave like I wanted. I really like the outcome though.
The way it works is that the Game of Life is overlaid on a larger grid of audio regions, making an equal temperament scale with octaves on the y axis and octave divisions on the x axis. The more cells that are alive in a given audio region, the louder it gets relative to the others. The regions are also marked with colour for extra pretty.
You can scale up the grid and the audio regions to pretty large sizes, but I didn't find many settings that worked as well as these. 12-tone is traditional western music, but you get a lot of dissonance when there's too much going on. The 5-tone is apparently very similar to Gamelan music, though I suspect an actual gamelan musician might have something to say about that.
More details and a bigger demo are up on Github.