So, yesterday, I caught him in action, playing in the crib when he should have been napping. I watched him go from laying on his belly to the sitting position. What a strong kid! I was so impressed. I let him stay in his crib playing, since he wasn't crying, hoping he would go to sleep. I went back a little later to check on him when it got quiet and found this:
curled over from the sitting position, head down on the mattress, sleeping. How is that comfortable?