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;
		}
		// TODO setHighScore();
	}