I've been working on a finished drawing of the pose for the last two weeks. Here are a couple shots of the piece as it progresses. I'm working very slowly: this pose is so complicated and fascinating. I find I have to take my knowledge of anatomy to another level to grasp it. The articulation of the action depends on particular bundles of muscle fibers within a given muscle. For example the center of the middle section of the deltoid. I'm learning a lot, but it is going very slowly. I think I have reworked the left shoulder twenty times and I'm still not happy with it.