And the Klein Bottle

The first step in the Klein bottle exploration - a maquette (unfired) cut in half lengthways to look at the inner workings and clarify the form in my mind, and to  find out what the technical challenges are in the making process:

This is one of the two crucial places - where outside becomes inside (or the inside becomes the outside if you're taking the movement/travel in the opposite direction)

And this is the other crucial place - where the inner cylinder folds over and out of itself, the inside thus becoming the outside (or the outside becoming the inside if you're going in the opposite direction) 

And a couple of close-ups of the inner workings - during the initial stages of construction: