“If we’re going to use physical ‘documents’ the way we use paper ones—glancing at them for an hour, or perhaps only a moment, then tossing them aside—we’ll need printing material to be recyclable, even biodegradable. Imagine the 3-D printing equivalent of a Post-it note! What’s more, we need our intellectual culture to evolve. Right now, we don’t value or teach spatial reasoning enough; “literacy” generally only means writing and reading.”