"I feel like this is an important idea, one of those ideas that your brain must wrap itself around slowly, the way pythons eat" (p.257) (Simile)
Quentin says this of a realization that the people around him have complex inner lives of their own (while playing "That Guy is a Gigolo" with Radar in the car). However, this quote is representative of Quentin's outlook and growth throughout the book. Coming of age is a gradual process, made up of small realizations built up and digested over time. Quentin demonstrates self-knowledge, and scientific learnedness, in this metacognitive simile.
"We play the broken strings of our instruments one last time" (p.305) (Metaphor)
As discussed in the Symbols and Motifs section, there are many different kinds of strings referred to in the book - strings that hold people together, the string on a balloon floating away, etc. In this quote on the last page of Paper Towns, Quentin speaks metaphorically of the strings of instrument that allow people to make music together, even if broken.
"We bring the fucking rain, Q. Not the scattered showers." (p.49) (Metaphor)
This quote is classic of Margo early in the book - fierce, curse-laden, and yet intelligent. Margo uses the phrase "bring the rain," which means to bring violence or justice to something, to compare her preferred type of action to Quentin's nervous and laid-back attitude.
"There was nothing built atop it, just the hole cut into the earth like a dead mouth agape" (p.211) (Simile)
Quentin's trips to the pseudovisions are often imagery-laden, and in one particular trip he finds building has not gone on at all, leaving this hole that he compares to a dead mouth. There is imagery of dead mouths as well in the book in relation to Robert Joyner and his feared image of Margo, to this comparison to the pseudovisions brings the three images of death together, strengthening the parallel of unfinished construction and unfinished lives - lives abandoned while still in progress.
"The human tongue is like wasabi: it's very powerful, and should be used sparingly" (p.213) (Simile)
Green flaunts his flair for humorous YA writing in this quote, at once insightful, funny, and disgusting.