Zoey is learning quickly how to sit unassisted. I thought it would take her longer than this, because she couldn't do it at all even a week ago. Then she learned how to do it on the bed, where the squish of the mattress helped stabilize her. The first time she did it I had her reclined back on a pillow and she sat up trying to get a better view of what I was up to. When she realized she was sitting she giggled several times and looked extremely pleased with herself. She likes to bounce up and down while sitting on the bed too, that is a good time.
Sitting on the bed helped her realize that she could do it, and now she can sit other places for short periods of time too.
But, there's still room for improvement.