Actually even higher level than that: it's all JavaScript, but it relies heavily on multithreading (see the linked Noita talk, which uses the same model). But basically:
The world is divided into chunks and the threads are processing them simultaneously in an even-odd checker pattern to avoid race conditions. When all pixels settle in a chunk it falls asleep and can be skipped altogether until an active pixel enters and wakes it up again.
The world is divided into chunks and the threads are processing them simultaneously in an even-odd checker pattern to avoid race conditions. When all pixels settle in a chunk it falls asleep and can be skipped altogether until an active pixel enters and wakes it up again.