In this one-of-a-kind story, a robot and a boy consider who -- or what -- makes a good friend. When a robot asks a boy, "Can we be friends?" the boy replies, "I don't think so. You're a tin can." The robot disagrees. And to prove that it is not a tin can, the robot shows the boy all that it can do: Play music Do math Bake a cake But the robot has no brain, the boy insists, and no heart. So surely it is a tin can. Is there anything...