Manifold
Other shapes can be manifolds too. For example, a hyperbolic plane is a shape that looks like a saddle or leaf of lettuce. If you try to press it down onto a piece of paper, it will have wrinkles, and it will go on forever past the edges of the paper. But you can make a map of part of it by squishing the edges, just like with the Earth you can make a map by taking part of it and stretching the edges.