Looking for a YC company (gaming) that posted a job here

I remember having seen a job post for a YC company but I can't find it anymore. The company was working on some kind of browser-based game where you can build whatever you want using elementary blocks. Sort of like Minecraft. I can remember reading that one of their advisor was one of the lead directors of The Sims or a similar game. Does anyone know what company I'm talking about?

thank you!