Azulene Conjugation?

I'm trying to figure out how azulene is an aromatic compound; I understand it is cyclic, flat, and follows Huckel's rule, but I don't understand how it is conjugated.


I have circled what I believe to be an unconjugated area in yellow. Can someone help me figure out how this molecule is conjugated? Thank you.


[![azulene conjugation attempt](https://i.stack.imgur.com/WSKRL.png)](https://i.stack.imgur.com/WSKRL.png)




If you insist on neutral atoms then the internal linkage is not conjugated.


BUT ...


The notable thing about azulene is that the seven-and five-membered rings can be aromatic when the former is positively charged and the latter negatively charged. That puts six electrons into each ring, and we all know about the $4n+2$ rule (even if technically it should be applied to single-ring systems).


If you allow a positive charge on the seven-membered ring and a negative charge on the five-membered ring, you can render contributing structures with a double bond in the internal linkage.


[![enter image description here](https://i.stack.imgur.com/00TeUm.jpg)](https://i.stack.imgur.com/00TeUm.jpg)


<http://www.chemspider.com/Chemical-Structure.8876.html>


According to [Wikipedia](https://en.wikipedia.org/wiki/Azulene), azulene is actually known with a dipole moment having the positive end in the seven-membered ring, and its chemical reactivity (electrophilic in the seven-membered ring, nucleophilic in the five-membered ring) is also consistent with this polar contributing structure.


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