Might come in useful, haven't checked myself but from what I remember this seems about right.
Code:
0 - straight walls, fences etc
1 - diagonal walls corner, fences etc connectors
2 - entire walls, fences etc corners
3 - straight wall corners, fences etc connectors
4 - straight inside wall decoration
5 - straight outside wall decoration
6 - diagonal outside wall decoration
7 - diagonal inside wall decoration
8 - diagonal in wall decoration
9 - diagonal walls, fences etc
10 - all kinds of objects, trees, statues, signs, fountains etc etc
11 - ground objects like daisies etc
12 - straight sloped roofs
13 - diagonal sloped roofs
14 - diagonal slope connecting roofs
15 - straight sloped corner connecting roofs
16 - straight sloped corner roof
17 - straight flat top roofs
18 - straight bottom egde roofs
19 - diagonal bottom edge connecting roofs
20 - straight bottom edge connecting roofs
21 - straight bottom edge connecting corner roofs
22 - ground decoration + map signs (quests, water fountains, shops etc)