Where do I find the XML Wall graphics files?

[Civciv5]

Where are the Walls graphics defined? I can't find where these are defined and I'd like to change the Wall graphics. I tried looking into the CityLSystem, but they're not there, neither are they in the PlotLSystem. Like the Wall graphics change between the Classical and Medieval ages, where is this defined?

 

[Nightinggale]

I'm not sure I will try to dig up the answer to this one. By the time I figured it out, you solved the problem yourself

It is actually a good question. For once a question shows up and not only do I not know the answer, I also draw a blank on how to figure out this issue. Searching the DLL code for "Wall" didn't help. All I found was some wall overwrite feature, which can be either on or off for each city, as well as setting some wall points, which presumably has to do with where the wall is placed, not which graphics are used for it.

Now you got me curious and I wonder how this is done and I await the all knowing (combined) knowledge of the forum users