def _ordered_edges(face_edges):
    """Returns "srce", "trgt" and "face" indices
    organized clockwise for each face.

    Parameters
    ----------
    face_edges: `pd.DataFrame`
        exerpt of an edge_df for a single face

    Returns
    -------
    edges: list of 3 ints
        srce, trgt, face indices, ordered
    """
    srces, trgts, faces = face_edges[['srce', 'trgt', 'face']].values.T
    srce, trgt, face_ = srces[0], trgts[0], faces[0]
    edges = [[srce, trgt, face_]]
    for face_ in faces[1:]:
        srce, trgt = trgt, trgts[srces == trgt][0]
        edges.append([srce, trgt, face_])
    return edges
