On Apr 23, Nicolas Bonneel <nicolas.bonn...@wanadooooo.fr.invalid> wrote: > > Supposedly, our universe is closed and finite, although the > > geometry and topology isn't precisely known. > > This means a straight line (geodesic) traveler > > must return to his starting > > poiint, yes/no? Hence, curved space. > > no - a flat torus... is flat, closed and finite, > and a traveler returns to his starting point.
? I'm a lifetime donut connoisseur, but have yet to see a flat one.
> Same for Poincaré dodecahedron for instance etc.