Not exactly a glass tool, but find here some variations on the famous topological model, the Klein Bottle. There is a good visual explanation about these objects discribed in a youtube video here.

The inimitable Dr. Cliff Stoll has come to us over the years to build him another crazy version of the borosilicate Klein bottle. Some of them are quite challenging, and some impossible, depending on the number of dimensions....!

He talks a little bit about the one on the right on a TED talk here, @ ~ 5:10 minutes in. 

Wine Klein Karafe 

A classic  for scientific glassblowers.

Torus

Cliff recently brought in a small 3D printed update of this object that is very nice, shown below.
Check out his website ACME Klein bottles.

And just for the record, ACME comes from Adams Chittenden and ME
- at least,  that's what Cliff told us ; )