Bisection Trick

Effect: A card is selected by the spectator and a piece of cardboard with a dashed cutting line is folded around the center of the chosen card - with just a snap of your fingers the card seems to be magically cut in half without any moves or whatsoever as you slide the top half of the card aside... Magically and visually the top half begins to move on its own and eerily slides back into position only to reveal the fully restored card.