Bill was at the skate park, trying to do new tricks with his skateboard, although they didn't work out. He had been there trying for more than an hour. When he was trying to do one of the tricks, he accidentally made his skateboard roll down the hill. Bill ran after it to try to stop it, but he couldn't catch it. The skate stopped rolling when the surface was flat and it slightly collided with a boy's leg. The boy looked at the skateboard and then saw another teenager (Bill) approaching.