Quadrophonic

A card is selected, and placed on the table face down. You explain that you'll reveal the card with the aid of your Quadrophonic computer - four cards shown blank on both sides has a "computer" printed on it. First, the computer must show the back of the selected card - and sure enough, the cards now develop four backs. Now the machine must show the face of the card - and does… four of them. You've printed nine surfaces on the blanks but the kicker is when you turn over the tabled selection. The computer has "canceled" the original selection, for that card now has a huge X across its face. Includes instructions. Very good condition.