Give three robots a rock and you’ll get three entirely different opinions about it. One presents it with the open-palmed pride of a genuine discovery, a second leans in, utterly captivated, and a third hangs back, unconvinced the thing is worth the fuss and faintly wary of it besides. The truth sits somewhere in the middle. It’s a rock. On the imaginary planet we dreamed these robots onto, as on ours, some mysteries turn out to be exactly what they appear to be, and half the fun is in the looking anyway.