New Skill: Rotating in Place

We've seen plenty of the rolling left and right, going from belly to backside and vice versa, but this one's new: rotating in place.  Anderson has been doing this for a couple of weeks, but we were finally able to take some snapshots of it.

Start position:

Five minutes later:

Most of the time he does this when going to bed or even while sleeping.  But we sometimes even catch him rotating on the activity mat and always in counterclockwise direction up to a full 360 degree turn.  Anderson will probably be able to start crawling soon (or just rolling around?).