Singular Arrangement of Sixteen Cards.—Take the four kings, the four queens, the four knaves, and the four tens of a pack, and ask if there be any one in the company who can form a square with them in such a manner that, taken in any direction, from right to left, from the top to the bottom, by the diagonal—anyhow, in fact—there will always be in each line a king, queen, knave, and a ten. Everybody will think the thing easy, but it is certain that no one will succeed in doing it. When they “give it up,” take the sixteen cards and arrange them as follows, when the king, queen, knave, and ten will stand as required.
The Card That Cannot be Found.—Take any number of cards and spread them out fan-like in your hand, faces fronting the spectators.
Ask one of them to select a card. You tell him to take it, and then to place it at the bottom of the pack. You hold up the pack, so that the spectators may see that the card is really at the bottom. Suppose this card is the king of hearts.
Then, pretending to take that card, you take the card preceding it, and place it at a point corresponding to A in the following figure.
A C
B D
You then take the card drawn, namely, the king of hearts, and place it at the point corresponding to B in the above figure. Finally, you take any two other cards, and place them at C and D. Of course, the cards are placed face downwards.
After this location of the cards, you tell the person who has chosen the card that you will change the position of the cards, by pushing alternately that at the point A to B, and that at D to C, and vice versa; and you defy him to follow you in these gyrations of the card, and to find it.
Of course, seeing no difficulty in the thing, and believing with everybody that his card is placed at the point A, he will undertake to follow and find his card. Then performing what you undertake to do, you rapidly change the places of the cards, and yet slowly enough to enable the person to keep in view the card which he thinks his own, and so that you may not lose sight of the one you placed at B.
Having thus disarranged the cards for a few moments, you ask the person to perform his promise by pointing out his card. Feeling sure that he never lost sight of it, he instantly turns one of the cards and is astonished to find that it is not his own. Then you say:—“I told you you would not be able to follow your card in its ramble. But I have done what you couldn’t do: here is your card!”