First of all: set up the pack by alternating red, black, red, black through the whole pack. Do this before your audience arrives. Now you are ready to start.
1. Tell a spectator to cut the pack as many times as they want.
2. Have them riffle shuffle it, but once only.
3. You cut the pack between two cards of the same colour.
4. Turn over the top card. If it is red, deal it to your left, face up. If it is black deal it to your right, face up.
5. Deal the next card face down underneath it. Repeat step 4, then this step (5) until the pack is gone.
6. The piles you have are mirror images. The cards underneath the red face up pile are black, and the cards underneath the black face up pile are red. Reveal this to everyone.
7. Take your well deserved bow.