The Columnist Manifesto

The other night, changing out of my hockey gear, I dropped my "cup" on the floor. The cup, for those of you who don't know, is the plastic shell worn to protect the groin area -- what Shakespeare would have called a "codpiece."

The cup bounced and bounced, an improbable number of times, covering a much greater distance than I would have thought possible, so that I had to walk several paces to retrieve it.

And like Isaac Newton pondering the falling apple, I wondered why that would happen.

This cup is very rounded. All cups are rounded, to be sure, but the ones I had formerly were shallow like an ash tray. This one was as rounded as "the Bean" in Chicago's millenium park.

That explains the bouncing, and I realized that the well-rounded codpiece is superior in design to less rounded models.

The controlling principle was discovered by designers of tanks during World War II.

The flatter a surface is, the more possible angles can hit it with a crushing , maximizing its moving force against the surface. The more curved the surface, the more likely it is that objects will strike it only a glancing blow, and deflect off.

The tanks that the Germans used to roll though Poland and France had flat armor plates in rectangular, boxlike shape. By the end of the war, tank designers on both sides had discovered the deflection principle: they got rid of as much of the right angled armor-plating as possible, replacing it with curved and sloped armor.

I bought my less curved cup many years after World War II. I don't know why codpiece designers were so slow to catch on to the concept of sloped armor. But I'm glad to be wearing the newer, more curved model when I think of those hockey pucks coming straight at me.