Mirrors are fascinating. They reflect nano-meter light waves in such a way that three mirrors set at different angles next to a light bulb create the appearance of more light bulbs, reflect the light in several directions and amplify the amount of light being produced.
What is the bandwidth of a mirror? We only observe the light frequencies, but does it also reflect microwaves and lower; maybe UHF, VHF, on down?
What if a 10-foot mirror next to a 10-foot antenna doubled and maybe aimed the signal in a desired direction? How about one of those 3-way mirrors from a department store dressing room. Would that cause a strong AM radio beam in a specific direction?