L2-41
Show how a corner reflector works in two dimensions.

A ray of light strikes the two surfaces of the corner reflector and returns antiparallel to the original light ray. For a three-dimensional corner reflector the outgoing light ray also leaves antiparallel to the incoming light ray. The lens keeps the ray narrow.

A set of three rays of different colors can also be used with this two-dimensional corner reflector to show that the rays return inverted with respect to their initial orientation.