Here's an earlier version of Emerald City.
Oscar Diggs had a the wall built because, of course, he's terrified of the wicked witches. The wall will be build taller, the city will expand over the years, and a lot of green paint will be used to eventually resemble the version we saw in chapter seven:

--but of course I also had to redesign the castle because I already redesigned it in chapter nine:

I'll probably redraw the castle bit of the city in chapter 7 to match before I publish the book.

The castle is also way too big in the far shot of the city, but that's just a purposeful abstraction because it looks good.