What could top the experience of designing your own obstacle course at the park playground and then following the path 51 times while Grandma rocks your sister in the stroller? You climb the steps, run over the deck, jump into thin air, land without falling, turn left, bounce up more stairs, go down the slide, and run around the perimeter to the starting place again. To heighten the experience, a new “friend” is right behind you and trying to keep up. You are invincible.