[What are the "three gilded balls" mentioned in FH?]

And the pawn shops in turn represent the trader principle, which is how all men should interact.

I'm not sure I agree with that sentence. As I see it, the tone Kent's using suggests something negative about the way humanity live their lives.

Take a look at the preceding sentence in the book:

"Thinking is something one doesn't borrow or pawn. And yet, If I were asked to choose a symbol for humanity as we know it..."

[What are the "three gilded balls" mentioned in FH?]

Kent Lansing : "... And yet, If I were asked to choose a symbol for humanity as we know it, I wouldn't choose a cross nor an eagle nor a lion and unicorn. I'd choose three glided balls" (The Fountainhead, p. 313)

I'm not sure I understand the last sentence. What does he mean by "three glilded balls"? what does it represent?

[the nature of jazz]

Improvisation, by definition, is "on the spot" composition.

In that sense, the only difference between the two is that the improvising musicians dont have an eraser.

About metheny, I wouldn't restrict the word "jazz" as describing only bebop/swing/whatever type of jazz you familier with. As said above, Pat Metheny's group plays composed music with improvised solos. In my book it's still considered 'jazz', as the solos are still the dominant factor most of the time