boardaftermove[secondtilespacecombinedtilescolumn[ boardaftermove[thirdtilespacecombinedtilescolumn[ boardaftermove[fourthtilespacecombinedtilescolumn[ return boardaftermove def askforplayermove() """asks the player for the direction of their next move (or quit ensures they enter valid moveeither ' '' ''sor ' "" print('enter move(wasd or to quit)' while truekeep looping until they enter valid move move input(''upper( if move =' ' end the program print('thanks for playing!' sys exit( either return the valid moveor loop back and ask again if move in (' '' '' '' ') return move else print('enter one of " "" "" "" "or " ' def addtwotoboard(board) """adds new tile randomly to the board "" while true randomspace (random randint( )random randint( ) if board[randomspace=blank board[randomspace return return after finding one non-blank tile def isfull(board) """returns true if the board data structure has no blanks "" loop over every space on the board for in range( ) for in range( ) if space is blankreturn false if board[(xy)=blank return false return true no space is blankso return true if this program was run (instead of imported)run the game if __name__ ='__main__' try main( except keyboardinterrupt sys exit(when ctrl- is pressedend the program twenty forty-eight