Rheo classification

Another instructive example is found in Fig. 2 The first three systems therein (r + he+ e) illustrate the same features as Fig. 1 with respect to the Kekule structure counts (/iQ. The systems are again obtained by successive additions of hexagons, but four hexagons are added each time in this case. The last system (Fig. 2), obtained by adding four hexagons into the corona hole of the e system, is a concealed non-Kekulean (o). This set of single coronoids illustrate nicely the rheo classification. 

Notice that the neo classification for the single coronoids with h = 15 is known 142388n + 29824e + 281734o. On the other hand, the corresponding rio and rheo classifications are not known. 

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