One-way deck
Encyclopedia
A one-way deck is a deck of playing cards where the back of the cards has a pattern which can be oriented to have a "top" and "bottom". Magician
s and card sharp
s can use the orientations of cards in one-way decks to encode information that allows them to perform card tricks.
A certain number of the faces of playing cards can also be used as "pointer cards" (the Seven of Hearts, for instance, whose odd heart image can point in one direction or another) which, when all aligned, allows an otherwise ordinary deck (one where the backs are all identical) to be used as a partial one-way deck.
In fact all sevens may be used in this manner because of the placement of the seventh marking, which is always on one side or the other of the median line. No other card can reliably be used in this manner although in many decks various clubs, hearts and spades can be used since these are different when turned over.
Magic (illusion)
Magic is a performing art that entertains audiences by staging tricks or creating illusions of seemingly impossible or supernatural feats using natural means...
s and card sharp
Card sharp
A card sharp is a person who uses skill and deception to win at poker or other card games...
s can use the orientations of cards in one-way decks to encode information that allows them to perform card tricks.
A certain number of the faces of playing cards can also be used as "pointer cards" (the Seven of Hearts, for instance, whose odd heart image can point in one direction or another) which, when all aligned, allows an otherwise ordinary deck (one where the backs are all identical) to be used as a partial one-way deck.
In fact all sevens may be used in this manner because of the placement of the seventh marking, which is always on one side or the other of the median line. No other card can reliably be used in this manner although in many decks various clubs, hearts and spades can be used since these are different when turned over.