I offered my contribution as a replacement for Dr. Gay's doughnut-shaped universe, which appears to be based on a misguided attempt to liken the shape of the universe to that of a modified 3-torus. In the latter, opposite faces of a cube are merely "glued" in the sense in which that word is used in topology. It appears to me that Dr. Gay sought, instead of gluing one pair of faces, to stretch the 3-torus along the normal to one pair of faces, then to bend that normal into a circle to join the faces, thereby producing a doughnut-like figure with a square cross section through the now-circular former normal. I described an analogical two-dimensional universe only as an aid to perception. It makes sense to me to suspect that the three-dimensional world that we experience is actually the three-dimensional "surface" of a four-dimensional hypersphere.

I feel that anyone who bought into Podcast 78 should be interested in this thread.