Busy
When Sam was a newborn, the most common observation was "he’s so alert." Now, it’s "he’s so busy." The 3 "big things" for him now are circling our house at varying speeds (getting faster and faster), figuring out which containers do or do not fit into each other, and pointing at any object that catches his fancy and saying something that sounds like "dat" which, if translated, means "what is that?" or "give that to me" or "how does it work?" or "can you take me to that?"
Busy busy busy.