The square was also below the level of the rest of the yard and had large post holes in it. His objective was to till the backyard so he could level everything out and then re-seed the entire area.
That darn shadow seemed to be following me all around town - causing less than perfect before and after photos.
Anyway, the following is the before and after for his project. By the looks of it, he took two passes across the yard. Looks like a good deep till and no noticeable grass material left.