From what the articles are saying it seems like they're either making an assumption of or are working in some non-Euclidean space, and the visuals are merely Eu

From what the articles are saying it seems like they're either making an assumption of or are working in some non-Euclidean space, and the visuals are merely Euclidean projections or representations, which are necessarily curved. (Warning: likely butchering the terminology, am not a mathematician)