And it doesn’t have an edge. Or, as the mathematicians would say, it doesn’t have a boundaryA Klein bottle is also a hollow tube whose ends have been joined. However, before the ends are joined one end passes through the wall of the tube, like a ghost through a wall, and travels down the tube to meet the other end.

It is important to realize that the wall of the tube is not breached it remains intact and continuous. This is possible because a Klein bottle is a shape, an abstraction, and not a material object.

It's a surface whose top and bottom are the same (non-orientable object). So, the Mobius strip is a one-sided strip (non-orientable). The Klein bottle extends this to the next dimension, which takes the object into a fourth spatial dimension. People only observe three spatial dimensions. Projecti...