def first_almost_matching_pair(strings):
    """Return the first two strings that differ by only one position"""
    for x in strings:
        for y in strings:
            number_of_differing_positions = sum(
                char_x != char_y for char_x, char_y in zip(x, y)
            )

            if number_of_differing_positions == 1:
                return x, y