A flat torus in three dimensional space
G
Master dregree in Physics in scattering theory. PhD in Physics in group theory (ray representation in quantum mechanics). After a master in e-learning I'm Chief Editor / Deputy Editor for EduINAF, INAF magazine about outreach and astronomy education.
A slight correction: The colourful illustration of...
A slight correction: The colourful illustration of the torus is just the standard way to depict a torus, but is nowhere near to being a flat torus. On the contrary: In this picture we can clearly see the positively curved regions (as on the top of the picture, where the surface curves down in all directions and looks like part of a sphere) and the negatively curved regions (imagine standing "inside" the hole, where the surface is curved like a Pringles potato chip).
