private void checkDead(){
		for (int row = 0; row < ROWS; row++) {
			for (int col = 0; col < COLS; col++) {
				if(board[row][col] == null)return;
				if(checkSurroundingTiles(row, col, board[row][col])){
					return;
				}
			}
		}
		dead = true;
		if(score >= highScore)highScore = score;
		setHighScore();
	}