I also love the image the way it is, but agree that it would be a great place to come back to and reshoot. Be aware also that the sun sets and rises at a different place day to day, and to get a specific placement of the shadow on the wall may take months. Even then, you might find that the season or lighting isn't perfect those days. If not, come back in 6 months and the sun will be in the same position. Seems to me like it,d be a fun long-term project.