It doesn’t work while driving because the compass doesn’t like being turned on its side, as it is when you work car pedals. Magnetic fields mess it up (of course) and I can feel it circling my foot on escalators or seeming to vacillate directions randomly as I rest my foot on the floor of the subway. But that’s interesting too — to feel the specific places where infrastructure interferes with the Earth’s magnetic field.

I returned home to Washington DC to find that, far worse than my old haunt San Francisco, my mental map of DC swapped north for west. I started getting more lost than ever as the two spatial concepts of DC did battle in my head. Eventually, the Northpaw won, and the NW/NE/SW/SE on DC street signs started making a whole lot more sense.