Auditorium cove corner and brick quoins

The auditorium has a large plaster cove where the walls meet the ceiling. In the outermost corners, there is an overlapping corner that is much more complicated than the others. Two of these complex corners were covered by the recent renovation, but the corners in the balcony still exist just inside the doorway:

I have tried several times to model this in Blender, but finally figured it out using 12 different Boolean modifiers for the 6 corners. The orange squares are where I made the slices (one seems to be hidden in this screenshot):

Also, after a lot of tedious UV mapping, I created the brick quoins which are on all the exterior convex corners of the building:

The texture looks a bit repetitious when viewed close-up, but this is not a problem when viewed from afar.