Cambio de cara en tarjeta de 0,1 seg en el aire

Four cards are selected and presented face down. One card is placed face down on the table. Just to make sure there are only 3 cards remaining, the performer counts them. The cards are lined up in hand and turned over to show 3 different cards. The fourth card on the table is flipped over to form a pair. A flick of the wrist and a pair becomes a 4-of-a-kind right before the spectators' eyes!