In the early 1970s, I made my sculpture 'Revolving Tower' for a major exhibition of kinetic works at the Hayward Gallery. Revolving Tower was made in three sections which were clad in a thin skin of mirror-polished stainless steel. Two drive motors situated in the bottom and middle sections paused individually for varying times from ten seconds to two minutes, to produce a cycle of frozen and moving relationships.
See a video here
The idea for this piece came from an adjustable stove pipe joint which I had seen in a hardware store in America. I was immediately delighted by the simple versatility of this unassuming object, yet puzzled by the paradox it seemed to present.
What appeared to be a cylinder was sliced at an angle of 11 degrees in two places, the cuts producing what one would expect to be an elliptical cross section, yet the sections were able to revolve in register with each other, indicating that they were circular. The answer lay in the fact that the tube itself was not cylindrical but elliptical in plan so that the angled cuts were circular.