IMAGINE that you and your brother, Jorbo, have accidentally created a robot that looks like a small ball. It hovers above your head and disappears whenever a stranger is around, becoming invisible in the present because it has entered a few seconds into the future. Jorbo awakens one morning to find he also has a small ball above his head."How many of these things are there going to be?" he whispers fearfully to you.You don't even want to think about...