Change stick angle--it essentially twists the right ring, twisting the cylinder of sticks into a hyperboloid. Spacebar for real rings, wood sticks and rubber bands.
Simulated with sine and cosine. Spacebar for clip of one I made with sticks attached to rings. Twisting a ring puts sticks into an angle, forming a circular hyperboloid ("rotational paraboloid"). See also my hyperbolic paraboloid.
