Out of This World (card Trick) - Effect

Effect

1. The performer takes a deck of cards, and places on the table two face-up "marker" cards, one black and one red; the black on the left and the red on the right. The performer tells the subject that he or she is going to deal cards face-down from the deck and the object of the exercise is for the subject to use the power of their mind to identify whether each card in the deck is black or red.
2. The performer takes one card at a time from the deck, face down, and asks the subject to attempt to divine whether it is black or red. The subject states their choice, and the performer then places the card in line with the appropriately coloured marker card, overlapping it at the bottom.
3. About halfway through the deck, the performer stops and announces that it is necessary to switch sides, in order to prevent a possible preference for one side over another from confusing the results. The performer deals two new marker cards onto the existing lines: a red one on the left, and a black one on the right.
4. The performer then continues as before, dealing cards face-down from the deck onto the subject's choice of the black or red line.
5. When the deck is exhausted, the performer instructs the subject to gather up and somehow reveal the left-hand line of cards; the performer does the same for the right-hand line.
6. The exposed lines reveal that every one of the subject's guesses was correct, and the black and red cards have been exactly sorted by colour.