Due to parallax from ADOP Orthoimagery, the roof and the base of buildings are at different locations. This is why you can see the west wall of 90 degree buildings in this imagery. Since you need to map the base of buildings rather than the roofs, I mapped Carl Stuart's buildings by using its shadows and west wall's base as a reference, which resulted in a base that agreed with most other imagery available. I am not sure if this is the proper way to map, as I am still relatively new to this, so correct me if I am wrong.