def one_quarter_right_rotation_wall(wall):
    """
    Return the wall coordinates rotated by 1/4. This assumes the wall is defined for a 4×4 board.
    """
    (i1, j1), (i2, j2) = wall
    return  ((j1, 4 - (i1 + 1)), (j2, 4 - (i2 + 1)))