The rise of the internet in the 1990s suddenly gave people the ability to talk and form communities about all kinds of weird niche hobbies and mysteries that, as isolated individuals, they previously had to muse over in silence. One of these, I remember, was the "Toynbee Tiles", linoleum squares left on the streets of Philadelphia over these years that contained the cryptic message "Toynbee idea in Kubrick's 2001 Resurrect dead on planet Jupiter". (It's an odd American analogue to the mysterious man in Australia who used to go around scrawling "Eternity" everywhere.) The Toynbee tile maker was ...