Reminded me of the circles in the sky method that might help studying the topological structure of the universe. https://mphitchman.com/geometry/section8-3.htm

Reminded me of the circles in the sky method that might help studying the topological structure of the universe. https://mphitchman.com/geometry/section8-3.html https://mphitchman.com/geometry/section8-3.html (I think I read about it first in “The shape of space” book)