Footnotes and endnotes in a book are interesting, not just because the content of the notes, but also because of what notes do to the reader, how they break up narrative flow, how they force eyeballs and concentration to leave the body text momentarily for some other text that might amplify the narrative or be ancillary to it or be a fascinating digression or something altogether unnecessary. A few years ago I read David Foster Wallace’s Infinite Jest, a book whose endnotes have footnotes, in hardcover. Halfway through the book I realized that the act of flipping pages—one page at a time, or to a page at the end of the book and back again—was as important (and as arbitrary) as the act of scanning text with the eye line-by-line. It was a powerful moment when I realized how form could be used, even in traditional media (e.g., a physical book), to mount a conceptual challenge against the modern world.