def _scatter_projected_facet(ax, facet, **kwargs):
    """Scatter the corners of a facet onto the composition plane

    Parameters
    ----------
    :ax: mpl axis
    :facet: from scipy.Hull
    :kwargs: Polygon arguments
    :returns: ax


    Returns
    -------
    mpl axis

    """
    coords = facet[:, [0, 1]]
    ax.scatter(facet[:,0],facet[:,1],**kwargs)
    return ax