When two of their edges are glued together, the result is a Klein bottle.
This shape is the simplest example of a nontrivial fiber bundle over the circle with each fiber equivalent to the unit interval. When a disk is sewed along this figure's edge, it becomes a projective plane. When two of their edges are glued together, the result is a Klein bottle. A primary example of a non-orientable surface, attempts to cut this shape lengthwise result in a shape twice as long. Name this shape with a one-sided surface often realized by a piece of paper taped together with a twist.
This shape is the simplest example of a nontrivial fiber bundle over the circle with each fiber equivalent to the unit interval.
Möbius strip