Desktop Poincare sphere - modelling polarized light

Here's an updated version of my Poincare sphere, with the coordinates on the outside, and a swivellable ball on the inside. Should be much easier to 'fidget' with, and use in demonstrations.

(For those that haven't seen it yet, the Poincare sphere is used for modelling the different ways light can be polarized: https://en.wikipedia.org/wiki/Polarization_(waves)#Poincar%C3%A9_sphere)

The sphere itself is there, and the stokes axes (S1, S2, S3) are labelled with their extreme points (Horizo