Share 'Umbilic Torus'

Trying to learn a bit about mathematical surfaces and how to build them in GH using the expression editor. This was a pretty interesting one I came across on the Internet of a form called an Umbilic Torus. It's like a Moebius Strip in that it only has one edge, but it is a 3D form. This definition also puts to good use a method for creating tree data from a single list, a problem I had that I go…