What quote in turtles all the way down has a metaphoric?

The Conversation of Aza’s Friends at Lunch (Metaphor)

In the first chapter of the novel, Aza describes her friends’ conversation using the metaphor, "the rushing of a river over a rock." In her statement, she has likened the conversation to the sound of a river passing over a rock. She uses the metaphor because she had stopped listening to them so that their conversation became a mere sound to her.