gistfile1.py

    def recursive_word_is_valid(word, board, pos):
        """
        
        Arguments:
        - `word`: the remainder of the word to be searched.
        - `board`: the current board.
        - `pos`: the current position in the board.
        """

        if board[pos[0]][pos[1]] == word[0]:

            char = board[pos[0]][pos[1]]
            board[pos[0]][pos[1]] = -1
            
            for x_mod in range(-1,2):
                for y_mod in range(-1,2):
                    found = recursive_word_is_valid(word[:1], board, (pos[0]+x_mod, pos[1]+y_mod))
                    if found:
                        return True
                    
            # The next character was not found.
            # Leave the board unchanged.
            
            board[pos[0]][pos[1]] = char
            return False
        
        else:
            return False
        
    def scan_for_first_letter(word, board):
        """
        Scans the board for all occurences of the first letter, then begins the recursive
        search on each of them.
        
        Arguments:
        - `word`: The word to be searched for.
        """

        char = word[0]

        for x in range(len(board)):
            for y in range(len(board[x])):
                if board[x][y] == char:
                    return (x, y)
        
        return None

    def validate_word(word, board):
        """Returns true if word can be made using the letters
        on the board.
        
        Arguments:
        - `word`: The word to be validated.
        - `board`: The current board.
        """

        pos = self.scan_for_first_letter(word, board)

        result = recursive_word_is_valid(word, board, pos)

        return result