two mirrors: corner cube reflector in 2D blue mirror

Image illustrating rays striking first one mirror and then another mirror placed at right angles to the first mirror. Notice how the rays are sent back along their original direction. This is similar to a corner cube reflector, except that a corner cube has three mirrors at right angles to each other, so that a light pointing at the corner cube from any position will be reflected back parallel to their original direction. Each mirror reverses one component of incoming the light.