What's better than a card trick? Predicting the FREAKING FUTURE, which is exactly what you'll do in this scam. We call it Pigment Prediction.
THE EFFECT: Your mark shuffles the cards as they like, while you write a simple little prediction. Once the cards are shuffled, the mark turns over the cards two-at-a-time, and sorts them in the following piles:
- If both cards are red, place them in a "red" pile.
- If both cards are black, place them in a "black" pile.
- If both cards are a mix of one red and one black, toss them into a "discard" pile.
Once the deck is sorted, have them count and tell you the number of cards in the "red" and "black" piles. For example, we'll say there are 14 red cards and 10 black ones. Now, show them your prediction, which clearly reads "THERE WILL BE 4 MORE RED CARDS THAN BLACK"
PART 2: even better, you can REPEAT the effect: Write a new and different prediction. Have the mark repeat all the same steps. This second time, both the red and black piles will be even...and that's exactly what your prediction will say: "BOTH PILES ARE EVEN".
THE WORK: First off, you might have trouble believing this, but with a full deck of 52 cards, no matter how much you shuffle them, when you pull off the top 2 cards and separate them into piles, you will always end up with some number of discards, and two even piles of red and black. (If you think about it mathematically, it makes sense. If you don't want to think about it mathematically, just try it a few times and you'll see this is true).
So how do you get 4 more red cards than black ones? By removing 4 black cards and leaving them in the box before you do the trick. Now, no matter what the mark does, if he counts correctly, there will be 4 more red cards in the piles than black cards (which is exactly what your first prediction will say).
The second time you perform this trick, make sure to add in the 4 extra black cards, making the total number of red and black cards even (52 total cards). Make sure your second prediction reads "the piles are even", and you're home free.