A couple of days ago Mercedes decided to roll over. She has only done it the one time, so nobody really believes me, but it happened. I put her down for a rare tummy time when both siblings were sleeping and there was no danger of being stepped on, and she instantly flipped to her back. I ran to get the camera and she refused to do it again.
(I didn't order this picture but I thought it was pretty cute, or at least funny.)