Quite interesting, this is a really fun thread to read...I would say the first thing is that he didn't sleep and seemed bored...like he didn't know what to do. The second was that he didn't put things in his mouth. Also very early he LOVED books, would crawl and find the ones he wanted to look at and sit and turn pages even by himself. And the biggest earliest thing that confused me was when he would match letters of the alphabet with other alphabet shapes and crawl around with pairs: P and D, L and T, W and M, O and Q, B and R, A and V, Z and N. It was quite interesting how he would only choose those pairs. It took me a while to realize there was a pattern based on shape. This was way early, when he was like 10 months old. Anyhow, those were pretty good cues something is up.