How does Ayn Rand use imagery in The Fountainhead?

Imagery:

No two sites on earth are alike. No two buildings have the same purpose. The purpose, the site, the material determine the shape. Nothing can be reasonable or beautiful unless it’s made by one central idea, and the idea sets every detail. A building is alive, like a man.

They stood straight, facing each other for a moment, as if at attention; it was almost like a military salute.