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DaveC426913

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In his analogy to a video game screen, he demonstrates how, as in Pacman, if you exit side of the screen, you reappear at the other side, same with top/bottom, so it is with a flat universe - if you continue in one direction long enough in a zero-curvature universe, you will eventually wrap around, and arrive back where you started. He says that, mathematically, this is called a "2 dimensional torus".

???

Colour me hogtied, but I thought that was the quintessential closed, curved universe (be it spherical or toroidal). i.e.:

*the way you get*3 dimensional space to loop back on itself

*is*to bend it in the 4th dimension so that it is a 4D sphere or torus.

A zero-curvature universe would very definitely NOT loop around like a video game screen, it would continue on forever.

Am I misunderstanding?