public void removeFullRows() {
        for (int row = getHeight() - 1; row >= 0; row--) {
            for (int col = 0; col < getWidth(); col++) {
                if (board[row][col] == null) {
                    break;
                }
                if (col == getWidth() - 1) {
                    moveRowsDown(row);
                    row++;
                }
            }
        }
        setChanged();
        notifyObservers();
    }