Kaleidoscope by Roy Walton

This effect centres around four playing cards. Three of them are shown to have the same back design, whilst the fourth has a contrasting coloured back.

The odd backed card is placed face down on the table and the faces of the other three cards are now shown. You explain that the odd backed card is an identical duplicate of one of these three and the object of the experiment is for the spectator to remember the cards and once the tabled card has been added, he is to tell you which card he thinks has been duplicated.

The tabled card is now added and the faces of all four cards are shown. The spectator is convinced that he knows the identity of the odd backed card, yet he is completely wrong! The odd backed card is shown and is seen to be an entirely different card to the one the spectator named!

To add further insult to injury, you now show that the two duplicates have entirely different back designs. Everything is now examinable.