Tessa often notices patterns. Watching people going about their ordinary business on the street after she has just escaped from the hospital, she thinks, “We make patterns, we share moments. Sometimes I think I’m the only one to see it” (266). Near the book’s end, when she is on the verge of dying, she finds meaning in the way separate events in her life have formed the pattern of her existence: “Moments. All gathering towards this one” (327).

This abstract thinking echoes Tessa’s need to find preciousness and meaning in the randomness of life, a need that healthy people do not have. She sees patterns as things that people create, in order to impose meaning on chaos. 

Tessa looks to the natural world as a way to understand her own condition. Images of decay fascinate her—for example, the dead rook that her brother Cal buries in Chapter 19—as do images of creation and renewal. Near the end of her life, she ruminates on the creation of the universe:

the big bang was the origin of the solar system and only then was the earth formed and only then could life appear and after all the rain and fire had gone fish came then insects amphibians dinosaurs mammals birds primates hominids and finally humans.