Amos and I were walking out of the gym after basketball practice last weekend when he saw a friend inside the lobby. He bolted to the window, rapped on the glass, and began performing a very particular dance. He put one hand—fingers in the shape of an L—to his forehead; his legs jutted back and forth like a dancing bear on a pendulum. Puzzled, I watched. Then I pulled out my phone. “Siri, show me a dance with an L.
