y coordinates of the arrow base.

        dx, dy : float
            The length of the arrow along x and y direction.

        width : float, default: 0.001
            Width of full arrow tail.

        length_includes_head : bool, default: False
            True if head is to be counted in calculating the length.

        head_width : float or None, default: 3*width
            Total width of the full arrow head.

        head_length : float or None, default: 1.5*head_width
            Length of arrow head.

        shape : {'full', 'left', 'right'}, default: 'full'
            Draw the left-half, right-half, or full arrow.

        overhang : float, default: 0
            Fraction that the arrow is swept back (0 overhang means
            triangular shape). Can be negative or greater than one.

        head_starts_at_zero : bool, default: False
            If True, the head starts being drawn at coordinate 0
            instead of ending at coordinate 0.

        **kwargs
            `.Patch` properties:

            %(Patch:kwdoc)s
        r