Available from http://www.world-of-magic.co.uk
Effect
Four-of-a-kind cards are shown and turned face down. The back of each cars is shown to have a Blue back. The performer asks the spectator Which one of the cards had a Red back The spectator responds with None.
...The performer says are you sure I think you may be snow blind. The performer turns the four cards face down showing them each to ahve White backs