This intense heat they project in a parallel beam against any object they choose, by means of a polished parabolic mirror of unknown composition, much as the mirror of a lighthouse projects a beam of light.
VOA: special.2010.09.01
Each mirror acts as a beam-steering device, controlling whether a single picture element (pixel) in the image is light or dark.
While the driving lights are the first use of a laser beam reflected off a mirror, the daytime running lamps, with their characteristic "torch" effect, and the indicator lights use LEDs.
We took down a mirror above her mantelpiece because we were told that a beam could be transmitted into the room to listen to a conversation in that room.