<Li> Double Decker Checkerboard: For a slightly easier version of the two - pack game, use decks with different backs and shuffle them separately . Deal them out in a checkerboard pattern (red, blue, red, blue, etc .) The different backs help identify the position in the grid and significantly reduce the possibility of which cards will match . </Li> <Li> Fancy: The cards need not be laid out in a strict rectangular grid and many players have their own special layouts that include circular, triangular, or diamond - shaped formations . Dealers may select any layout they wish . </Li> <Li> Spaghetti: Same rules as standard concentration, only the cards are not laid out in neat rows . They are strewn randomly about on the floor . </Li> <P> Concentration is not limited to playing cards . Many versions of the game that are designed for children may have different themes . In some computer versions, the cards may randomly move to increase the difficulty . </P>

How many cards are in a memory game