Concentration can be played with any number of players or as a solitaire or patience game.It is a particularly good game for young children, though adults may find it challenging and stimulating as well.Standard rules need not be followed: the cards can be spread out anywhere, such as all around a room.If they are not of the same rank and color, they are turned face down again and play passes to the player on the left.Concentration may be played solo either as a leisurely exercise, or with the following scoring method: play as normal, but keep track of the number of non-matching pairs turned over (this may be done using poker chips, pennies or by making marks on a sheet of paper).With perfect memorization and using an optimal strategy, the expected number of moves needed for a game withIn some computer versions, the cards may randomly move to increase the difficulty.