She Flies Through the Air
I just cleaned the walls in my house and pondered one of the mysteries of the universe. My cat-graceful daughter is a human who participates in no fewer than three sports and does, I might add, pretty well in all of them. Her reaction time is fast enough so that more than once when I've dropped something from the kitchen counter and she's caught it before it hit the ground; one time she did while balancing on one foot. She is, in sum, an agile child.
And yet she cannot walk down a hallway, or into a room, or around a corner, without touching the walls. It's like a chair-rail of fingerprints. Either the god to whom children answer demands sixty-eight wall-contacts each day, or moving while not on a sporting field makes her dizzy.
Or, more likely, healthy and active children do, in fact, bounce off the walls.