This projects displays views of the Moebius strip, a non-orientable surface with boundary, easily realised by gluing the two ends of a strip of paper after a half-twist.

Here is a stereographic image: look at the left picture with your right eye and at the right picture with your left eye to see it in three-dimensions.

Other views from random angles.

A strip with any odd number of half-twist is topologically equivalent to a Moebius strip, wherease a strip with an integer number of twists is orientable and topologically equivalent to a cylinder. Here is a triple half-twist Moebius strip, again as a stereographic image.

It is also possible to embed the Moebius strip in space in such a way that its boundary is a perfect circle. This embedding is called the Sudanese Moebius strip