Tri-foranderlige kort

First of all, the magician asks a spectator to select two cards. Next he places four cards with wrong printing above one of cards that the spectator chooses. Then he takes away the four cards.To our surprised,the four cards turn into the same pattern as the card that the audience appointed. After that the magician try another card with the four cards. It also changes into the same pattern as the appointed card. The four cards can be transformed one more time.They will all change into blank card. This is so-called Tri - changeable Card.