[ars]

We don't really know that. Let's suppose the universe was really 4D. We don't currently know if the universe is flat or not. A curved universe can be both unbounded and finite which would be very elegant.

Einstein proposed a test to find out. I'm hoping this test will eventually be Gravity Probe D (Probe C will be a repeat of the failed Probe B).

[lmm]

We're talking about a game. We know exactly what geometry the game world has.

[ars]

No we are not. He asked about the speed of light.

And the game world has some super weird discrete geometry anyway.