Tenyo - A Whole New Hole

Magician displays 2 cards, each card has a round hole at the center.
One card is chosen by spectator and the spectator makes a magical gesture towards to the other card.
In the next moment, the round hole transforms into square hole!
The card is handed out to spectator immediately to make sure it is a rigid square hole!

Special material and unique ideas allow you to perform this mysterious effect easily, without hassle.