Sal the Magician asks you to pick any five cards from a standard deck (52 cards), 13 denominations (2,3,...,10, J, Q, K, A) and four suits (diamonds, hearts, clubs, spades). You do so, and then show them to Sal's assitant Pat, who places one of the cards back in the deck and puts the remaining cards into a pile. Meanwhile you shuffle the reduced deck of 48 cards several times. Sal is blindfolded, and does not witness any of this. Then Sal takes off the blindfold, takes the pile of cards that Pat arranged, examines it, and then picks out your fifth card from the deck! The deck of cards is not marked, and there is no verbal or visual communication between Sal and Pat. Without supernatural powers, how does Sal know your fifth card?