Borges: “The universe (which others call the Library) is composed of an indefinite, perhaps infinite, series of hexagonal galleries.”

Chiang: “It has long been said that air (which others call argon) is the source of life.”

Additionally, both stories end with the narrator drawing comfort from imagining a universe which extends beyond what is commonly conceived of as the boundaries of the one he inhabits.  Borges’s story uses combinatorial complexity as the basis of its thematic explorations, while Chiang’s uses the laws of thermodynamics.  Basically, Chiang has written the physics-y version of my favorite math-y story ever, and has thus made my inner scientist very happy.