Does what it says on the tin… and does it gloriously, too. What a super piece of work! Can’t tell you much about it beyond that it’s signed by someone called Ward Shelley (if I’ve read the handwriting correctly)*, and that I saw it via the tweetings of Adam Rothstein and Justin Pickard. Click through for the huge original version, and prepare to lose twenty minutes of your day in sheer wonder.
[ * Addendum: it's an entry to the seventh iteration of the Places & Spaces: Mapping Science contest, which looks like it contains all sorts of other interesting stuff. ]