I've been reading a little bit about toruses and spheres, but I am new to topology. In my reading I came across a discussion of whether a square grid could be represented on a sphere without a "singularity" of vertices. (This is in the context of cellular movement in a grid with a toroidal topology.)
There was an answer that suggested that "You can in fact have a normal square grid which has a spherical topology instead of toroidal. The way to do it is to use the fundamental polygon."
I liked that answer very much because it led me to Riemann, who I've been wanting to learn more about, but is this answer correct? Is the idea worth pursuing?