Fully Packed Wallet Appearing Cards (Joker Magic)

The magician will demonstrate the impossible; that is that two solid objects can occupy the same space at the same time! He takes out two cases that have been pushed together. He draws a red-backed card from the red case which he then presents to the audience. A member of the audience chooses a card from the deck and notes it. The magician replaces the deck in its case then opens the blue case and takes a blue-backed deck out of it! Among the blue cards is a red card which is none other than the card chosen by the member of the audience!