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by theOnliest 4159 days ago
I've always found these images [1,2] from Wikipedia to be helpful in explaining how the torus is a product of two circles.

[1] http://en.wikipedia.org/wiki/Torus#mediaviewer/File:Sphere-l... [2] http://en.wikipedia.org/wiki/Torus#mediaviewer/File:Torus_cy...