A joke my mother told me. A groundskeeper in France was sweeping the driveway to an apartment building in Paris. *Sweep* *Sweep*. *Sweep Sweep*. So it went for about an hour, with regularity. *Sweep Sweep*. *Sweep Sweep*. Suddenly he came to a spot with a very annoying patch of dirt. In an attempt to get it off he began to use more force and speed. *Sweepsweepsweepsweepsweepsweep* Suddenly above him he hears a window slide open, and a man sticks his head out and shouts: ""Monsieur, you're messing up the rhythm for all of Paris!""