Theo Spark

Mother Superior and her chief assistant nun had been out on missions of importance, riding their bicycles through the narrow streets of the small European village. Suddenly they realized they'd be late for dinner if they did not hurry back to the compound. Racing through the streets they took a short cut through an alley-way paved irregularly with old rocks.

The younger nun yelled forward, "Gee, I've never come this way before!" to which Mother Superior answered, "It must be the cobblestones!"

H/T HJB