PHOTONS HITTING A CORNER CUBE REFLECTOR
Animation showing a light source (LASER) firing red photons at a corner cube reflector. The photons are reflected in a way analogous to balls bouncing from a surface. The three reflective surfaces are at right angles to each other, and so they systematically reverse the direction of the three components of the light ray. The ray then goes back towards its source, parallel to its original course. It doesn't matter which angle the incident beam strikes the corner cube reflector, the reflected beam always goes back parallel. Red reflectors on tail lights use this principle.