The method of Sherlock Holmes

Take a deck of cards, lay on the table from the top deck of cards and a few turn away. Ask any member of the audience, he turned to any of the card by 180 degrees. Then you turn around and imitating Sherlock Holmes, start carefully inspect the card for this can take a magnifying glass. After inspecting the cards you show the card, which was launched a spectator.
Focus The secret lies in the fact that the drawings made card backs are not exactly in the center of the map, ie the distance from the edge of the map to a pattern with one side more with respect to the distance from the edge of the card to the pattern on the other side. This feature you use when trying to post cards on the table. All cards must be oriented in one direction by a certain distance from the edge of the map to figure shirt. The map viewer is launched, a pattern begins to stand out among the other shirts cards. Therefore, to find the card you will not be difficult.