Yesterday I witnessed this hysterical interaction between Jack and Jonathan: I heard Jack talking in the hallway and when I went to investigate I found him waving a toy car (with flashing lights and sounds) under Jonathan's nose. When Jonathan reached for it Jack snatched it away and ran a few steps down the hall. There he sat down and waited for Jonathan to crawl within reach, before jumping up and dragging the car a little further away. This he repeated, keeping Jonathan interested enough to follow, until he'd coaxed the baby into his room. Then he left the car, ran out the door and closed it, leaving Jonathan inside. He looked at me, clapping his hands, and said, "There! All done!"