Waving
Waving is a form of cheating in which the cheater bends or crimps cards so that the wavy card can be recognized in an opponent's hand or in the deck. It marks the cards without writing on them.
The simple explanation
A cheat who waves cards changes their shape slightly. He can then see where the card is, or know it when it is held. It is a way of marking cards.
A closer look
Waved cards are hard to see, but they can be felt or noticed when the deck is looked at from the side. Casinos change decks often and inspect them to find such cards. Players who suspect that cards are marked should tell the floor at once. It is a historical technique of card sharps.
A practical example
A dealer notices that several cards in a deck are slightly curved, and he calls the floor.
Full explanation
Waving is a form of cheating in which the cheater bends or crimps cards so that the wavy card can be recognized in an opponent’s hand or in the deck. It marks the cards without writing on them.
Waving is bending cards to mark them.
The cheater can recognize them later.
Casinos inspect and change decks.
Report suspicious cards to the floor.