What can be said about The Zodiac's sense of humor? Can this give us any clues into his mind?

He obviously loved the fact he had the area in his grip with his words. After such few attacks he could manipulate the public with his threats. I do not believe the "Bus Bomb" was ever real. Zodiac researched the building of a bomb but did he ever really intend to build/use one? Or was it just his sadistic way of driving fear into the public?

Zodiac must have sat back and laughed at the sight of police cars following school buses. Waiting for some maniac to shoot out the tires or a bomb to go off. It was such a success that other demands would have been made by The Zodiac and were in fact.

I think there may be more to this then just what I stated here. It may delve deeper into the whole Zodiac case. Was he just playing his idea of a mind control joke on the public?