\hbox{\vbox{ \hbox to 0.5\hsize{\hss \structure{\emostaromatatom{C}\swsingle\smostaromatatom{C} \wsingle\atom{C}\nnwsingle\wmostaromatatom{C}\nnesingle \nmostaromatatom{C}\esingle\atom{C}\sesingle\wmostaromatatom{C} \nesingle\nmostaromatatom{C}\ssesingle\emostaromatatom{C} \sswsingle\smostaromatatom{C}\nwsingle\phantatom{C}\nsingle \phantatom{C}} \hss} \medskip\hbox to 0.5\hsize{\bf Figure~4. \rm The azulene ring system.\hss} }\vbox{ \hbox to 0.5\hsize{\hss \structure{\longerewbonds\firstbicycloatom{C}\nnwsingle\atom{C} \eneabove\atom{C}\eseevoba\atom{C}\sswsingle \secondbicycloatom{C}} \hss} \medskip \vbox{\hsize=0.5\hsize\noindent\bf Figure~5. \rm Envelope form of the cyclo\-pentane ring.} }}