The very moment that my three-year-old niece picked up the little scrap of PVC pipe, I knew what would happen. I saw in my mind’s eye her baseball-bat swing into the back of her cousin’s head, and knew it for the inevitable truth as predictably as the quadratic formula. As he lay crying on the floor it occurred to me that, being what we are, certain objects speak to us. Tools meet the hand and, for better or worse, beg to be used. They inspire us to action, but we need not learn to obey them; on the contrary, we spend years learning to resist.