So Feynman and Heisenberg decided to take a road trip together, with Feynman driving and Heisenberg in charge of the map. Every so often Feynman checks with Heisenberg for directions.

"Where are we?"

"Forty three miles out of Tuscon. Take a left at the next exit."

This sort of thing continues for a while, everything's going well, when suddenly Heisenberg points: "Look out! Cop car behind the billboard!"

Feynman glances at the speedometer. "Relax, I'm going 55 miles per hour."

"Oh, way to go, bonehead," says Heisenberg. "Now we're lost."