“I need to make a shield to bring to school,” my 5-year-old son says in a matter-of-fact way as he drifts off to sleep at the end of a long weekend.  “Why?” his dad asks.  “The boys at school hit me, and I need to find a way to protect myself.  I keep telling them to stop, but they won’t stop, so I need to make some sort of shield.  It needs to be stronger than cardboard, but it can’t be metal because we’re not allowed to...