Pythagoras, Pythagorean, Euclidean, Gravitational Lensing, Symmetry.
adds up to the final result. This is just an example of how non-flat surfaces do not respect the sum of the internal angles. But what’s going on? To better illustrate the case, I present a spherical surface with 3 straight lines on it: Figure 7. “Straight lines” on a spherical surface. If you try