Years ago, I read a short story about the creation of an AI species. I believe they were described as crab-like. I remember the creator could speed up their evolution by letting the simulation run. Once they evolved language, the creator would communicate with them. Eventually, they discovered writing and math. After a few more sped-up iterations, they surpass human knowledge and finally find a way to escape safely into another dimension.
I cannot remember the name, and I cannot find it despite my best efforts with Google.