Card Trick 7 -- The Color Card Twin Towers

Thanks so much to Gregory for sharing this with us!!
"The pre-arranged deck effect is well-known, but this particular handling is by myself."   Gregory

Effect: 

The deck is split into two halves (towers), both of which may be shuffled by the spectator.  The spectator selects a card from either pile (his free choice!), and replaces it *anywhere* (his free choice!) into the other pile which he immediately shuffles.  The magician finds the selected card even after the spectator has shuffled the pile thoroughly!
 

Supplies:

• Complete deck of cards.
   

Preparation:

• Pre-arrange the deck by separating the cards into two piles of black cards & red cards.
• Place these two piles on top of each other to make one complete deck.
• Pre-arrange the deck ahead of time - don't let anyone see you do this!
   

Performance:

• Casually split the deck in half, creating two face-down piles (towers), one of the red cards, the other of the black cards.
   
• Let the spectator freely choose one tower, and select any card from this pile.  Do this by fanning out the cards face down, and have him touch a card, which he takes and remembers.
   
• Have the spectator insert his selected card anywhere into the *other* tower.
   
• Look through the tower containing the spectator's card.  The only different coloured card in the pile is the selected card!
   
• Produce the chosen card with your favorite revelation.  A simple method is to place the card on the table face down, and turn it over after the spectator names his card.
   

Tips:

• Keep the cards face down at all times, so that the spectator cannot see that each tower has cards of the same color!
   
• To heighten the effect, have the spectator shuffle each tower (face-down) thoroughly before making his choice.  Also have the spectator shuffle the pile thoroughly after replacing his selected card.  From the spectator's view point, the magician has not seen the chosen card, and can have no idea of its location because it is impossibly lost in the pile!
   
• To reduce the chances of the secret being "discovered", instead of separating the deck into red and black cards, separate it into odd cards and even cards (count jacks and kings as odd, queens as even).  At a glance, each pile will look like a random assortment of red and black cards, and the fact that the deck is pre-arranged will not be obvious.
   
• This trick is so mystifying that it *can* be repeated once or twice without risk of discovery! (but only when you are using piles with odd and even cards)
   
• For a variation with two spectators, have each spectator select a pile and a card, and shuffle their selected cards into the other spectator's pile.
   
• This secret of this trick may seem rather basic, but when played up, the effect is baffling for the spectator, especially since he shuffles the pile into which he replaces his card, so excluding any sleight of hand!