@Override
	public void undoMove() {
		if(!(old_states.empty())){
			int [][] last_board2048		= new int[rows][columns];
			last_board2048 				= old_states.pop();
			score 						= old_score.pop();
			int [] last_mosue			= old_mouse.pop(); 
			
			mouse[0] = last_mosue[0];
			mouse[1] = last_mosue[1];
			
			for (int i = 0 ; i < rows ; i++){
				for (int j = 0 ; j < columns ; j++){
					maze[i][j] = last_board2048[i][j];
				}	
			}
		}
	}