Comment by dreamcompiler

That's the idea, but it's like the 2D creatures know everything about the 3D creatures, which the 3D creatures find quite shocking.

The actual dimensionality is 4D to 3D once you add in time. But the math basically says an nD hyperbolic conformal manifold (AdS) can be completely described by its nD-1 boundary (CFT).* So I think it works in any number of dimensions.

*Oversimplified and probably wrong, but probably close enough for this discussion.