Today I was walking Talon to school and he was in a crappy mood as I had made him stop playing Twilight Princess and go to school.  We arrived at a crossroad and he was waiting for me to catch up.  The house on the corner has a wall and the ground cover from the wall to the house is river rock.  He picked up a rock about the size of a baseball and threw it down again.  It bounced and came right back up and hit him in the forehead.  He was shocked and dismayed.  I leapt on the opportunity to explain to him that this was a perfect of example of how life works.  When you get hit in the head with a rock-chances are you threw it.  Somewhere along the line you did something the put in motion the metaphysical machine that ends up hitting you in the head with a rock.