Assembly theory, a way to measure the complexity of an object in terms of the number of steps (from a preselected, general pool) needed to build it. https://nitter.net/0xmaddie_/status/1545250968341725185 via @Prathyush

Interesting, I think. So the key difference with Kolmogorov complexity is that it's computable, right? It seems like a special case Kolmogorov complexity but with a weaker programming language that doesn't have all it's interesting properties locked away by the halting problem.

Looks like it has found application in studying the chemical origins of life, where the only operation for creating complexity is just sticking molecules together. That makes sense. But it's pretty limited. Like I don't think it can detect the regularity in a bit-string like 101001000100001000001...

Reminds me of Minimal Description Length , which is also an approximate-but-computable variant of Kolmogorov complexity.