Reaching the end of a world map in a classic JRPG game sends you to the opposite end of the map. This is how most world maps worked back in the 2D days, and this is why these worlds are actually donut-shaped (or more precisely, toroidal), as WolfieMario's GIFs of Chrono Trigger show.
We might think it's a sphere or a globe, but that's not correct.
If you guessed "sphere" or "cube", nope, it's a torus. There's no way to wrap a map like this onto a sphere and still retain the type of motion shown in the game. Actually, it can be any shape homeomorphic to a torus. I won't get in-depth on what that means, as I'm not a topologist or anything, but to give an idea: a coffee mug with a handle can also have this map projected onto it.
The only question is: What's in the middle?
Chrono Trigger's world map [WolfieMario, imgur via Reddit]
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