I stopped at a fast-food restaurant recently. I was fascinated by a sign which offered Fat-Free French Fries. I decided to give them a try.

I was dismayed when the clerk pulled a basket of fries from the fryer, which was dripping with fat. He filled a bag with these fries and put them in my order.

"Just a minute!" I said. "Those aren't fat-free."

"Yes, they are. We only charge for the potatoes . . . the fat is free!"