vely, the number of flags, number of barbs, flag for
            half a barb, and flag for empty barb, ostensibly obtained from
            :meth:`_find_tails`.

        length
            The length of the barb staff in points.

        pivot : {"tip", "middle"} or number
            The point on the barb around which the entire barb should be
            rotated.  If a number, the start of the barb is shifted by that
            many points from the origin.

        sizes : dict
            Coefficients specifying the ratio of a given feature to the length
            of the barb. These features include:

            - *spacing*: space between features (flags, full/half barbs).
            - *height*: distance from shaft of top of a flag or full barb.
            - *width*: width of a flag, twice the width of a full barb.
            - *emptybarb*: radius of the circle used for low magnitudes.

        fill_empty : bool
            Whether the circle representing an empty barb should be filled or
            not (this changes the drawing of the polygon).

        flip : list of bool
            Whether the features should be flipped to the other side of the
            barb (useful for winds in the southern hemisphere).

        Returns
        -------
        list of arrays of vertices
            Polygon vertices for each of the wind barbs.  These polygons have
            been rotated to properly align with the vector direction.
        Ú