Watches the board for a change, waiting until any cards turn face up or face down, are removed from the board, or change from one string to a different string.
a Memory Scramble board
ID of player watching the board; must be a nonempty string of alphanumeric or underscore characters
the updated state of the board from the perspective of playerId, in the format described in the ps4 handout
Watches the board for a change, waiting until any cards turn face up or face down, are removed from the board, or change from one string to a different string.