Desire paths

I was told a story about an architect who designed a university building with no footpaths leading to it. The idea was to let students trail their own preferred paths through the grass, and then build the real paths over the well-worn dirt.

The story is probably apocryphal, but it's a cool idea.  Anyhow, today I learnt that this basic idea is called 'desire paths'.  And there's a subreddit dedicated to it, with lots of cool pictures, like this one.