A Moebius strip
The animation gives an idea of the generation of the Moebius strip from a rectangle. Two sides of the rectangle are pasted together after having imparted half a twist to the rectangle. The animation also explains why the Moebius strip is a non-orientable surface. You can see also another interactive animation.
© matematita
video di Domenico Luminati
The image belongs to the sections...:
The Moebius strip (Topology)
Topology (Animations)
Further information:
http://www.science.unitn.it/~luminati/