OPTICS ANIMATION / SIMULATION: Corner Cube Reflectors (Retroreflectors)

​Elastic balls are fired at a corner cube (three plane reflectors all at 90 degrees to each other). Each surface bounces the balls back in one axis. When the balls bounce off all three surfaces their direction has been reversed in each axis and so they travel back parallel to their original course. Light does the same thing with a corner-cube reflector, like those found in the red reflectors (retroreflectors) at the back of cars.

​A high-intensity beam of green light strikes a corner mirror (two plane mirrors at 90 degrees) and is reflected back parallel to its incident ray.  A corner cube (three plane mirrors all at 90 degrees to each other) does this in three dimensions. It is slightly easier to understand (visually) in two dimensions...