Abstract: I will introduce and  discuss some of the most basic fundamental concepts of  quantum physics by using orientations or angles in the plane, illustrated through linear polarisations of the light. 
Starting with the Euclidean plane, which is certainly a paradigmatic example of a Hilbert space, the orientations in the plane  are identified with the pure states.  Associating these quantum orientations with linear polarisations of light in the plane normal to its propagation constitutes an immediate and nice illustration  of the presented formalism. Another  contribution concerns the description of the dynamics of quantum states. The pure states form the unit circle (actually a half of it) and the mixed states form the unit disk (actually a half of it). Rotations in the plane rule time evolution through  Majorana-like equations involving only real quantities for closed (Heisenberg-Dirac) and open (Lindblad) systems.  Interesting probabilistic aspects  are developed.  Finally, I revisit light linear polarisation as  an example of quantum measurement through Stokes parameters.