I just opened Deflektor editor to test out something, and I opened used elements list in palette.

- nnaocasd.png (132.86 KiB) Viewed 2652 times
I found several unknown elements named rather as "Wooden wall (DF style)" or "Steel wall (DF style)". Once I pick them, I just get respective normal DF walls. After few seconds it hit me that since walls are mini-elements, which take 1/4 space of one tile, these unknown elements just represent different combinations of these sub-tiles (15 for each wall, to be exact), which means if I put all combinations for each sub-tile, which there is 6 of them in total (wooden wall, steel wall, wooden wall DF, steel wall DF, amoeba wall and ice wall), we can just flood the used elements list with 90 question mark elements, if not counting the actual
Letter '?' and
Unknown element.

- ewmfniwegd.png (234.82 KiB) Viewed 2652 times
Does that mean that each wall combination is it's own separate entity and we can even somehow apply different graphics for each shape? That could actually be pretty fun to mess around with.