A cylinder
If we take a long and narrow rectangle and paste together the two shortest sides, we get a cylinder (that is a sphere with two holes). What happens if we impress half a torsion before pasting them?
© matematita
immagine di Gian Marco Todesco
The image belongs to the sections...:
Cylinders and other spheres with holes (Topology)
From "fragments of topology" (From "XlaTangente")
Further information:
http://www.toonz.com/personal/todesco
