In Wednesday’s xkcd comic, Replogle has apparently been taken over by mad scientists. I’m having a hard time resisting the urge to explain the joke (I doubt many of my readers are physicists, but then I’m not one either). But in a weird Einsteinian way Randall is doing with globes and mass what Carroll, Borges and Eco did with maps and space: assume a 1:1 ratio between the map and the mapped.