[zenorogue]

More precisely -- you can have x,y coordinates, or (easier to work with) x,y,z coordinates, but you would quickly run into numerical precision issues, and that binary representation prevents that. (Probably it was HyperRogue, other hyperbolic games are wrapped or small enough to work without it. David Madore's hyperbolic maze has a wrapped world so it uses a totally different system. I think Sokyokuban also has tree-based representation of the map, even if the world is small. It could also be Hypermine by Ralith, it is also open world and open source.)