“You’re standing on the surface of the Earth,” Musk begins, according to the book. “You walk one mile south, one mile west, and one mile north. You end up exactly where you started. Where are you?”
This is an interview question from Elon Musk to job candidates. There appear to be two answers. The first, the north pole, is the obvious one. The second is not so obvious. At any point on a ring somewhere close to the south pole, you could walk one mile south, then turn and walk one mile west only to end up right where you started walking west (circumference would have to be 1mi), turn and walk one mile north to end up right back where you started.