This is a tough one - I want to clone an entire city. Exterior was easy enough, fly high above Bruma, drag a rectangle around the whole thing and copy. Move to the north side of Kvatch, paste it on the hillside, now I got a city exterior.
Next step is cloning Bruma world to link with the exterior - question is the interior of the city is made up of 15 different cells, how do I stitch all the duplicates together? Copying the whole smash and pasting into an empty cell is unlikely to work or they would have done it that way originally. Some kind of programming magic is probably involved in moving from one exterior cell to another, different from the Tamriel world because the city worlds are not actually exterior cells or interior cells, some kind of combination of both.