I hope my readers aren’t getting sick of seeing these photos. For Jill and me they’re very instructive. It’s hard to get them right, though, because we’re trying to get poses where our alignment is good, no distracting junk is in the background, the photos are in focus, and we’re not looking grim. Keeping the face and neck relaxed is part of breathing properly and being at ease in the pose – effortless effort.
This pose is very difficult for me because my hips and hamstrings are so tight. If I do it on the mat away from the wall, it’s a struggle to keep from flipping over backwards like a bug. All my focus goes into working with my hands and arms behind me. If I sit up on several blankets then only my heels touch the floor. Using a block at the wall gives me the benefit of being able to sit upright with the entire backs of my legs getting feedback from the floor. I can pay attention to extending out through my heels and stretching those adductors.
(I also posted this batch of photos so my sister in Massachusetts could see my new haircut.)
Practice Notes 
And the new haircut is what grabbed my attention first and foremost! Not that these pix aren’t excellent — they are, and so instructive! — but we definitely will have to discuss the hair (both of ours) later this month.