2 decks of card was show to spectator. Spectator pick one deck, and the other deck will be prediciton deck. They cut at any position, look at the card at that position. Even they can shuffle these 2 packs after cut, it will make sure magician do not know what top card is and what bottom is. The card will be return to middle of their deck. And in miracle, the position of their card in their deck, it will be also same position and same card at the prediciton deck