Here's a picture of Jack standing up at the reptile house. (In reality, he's just propped up against the railing - but it counts, right?) I think he's wondering when I'm coming back to rescue him from standing alone.
He wasn't 100% sure about the swing at the playground. One second he loved it, and the next he was about to cry. Literally. It was as if he had a split second to think about being scared on the way back, and on the swing forward he was having to much fun to be frightened.