Each level is 8 foot high, 4 levels on top, 16 squares, so 1(square) : = 2 foot.
Granite, or marvle, but quite weathered and rough, the roof is tilled, the roof should overlap the wall.
A receeding Forest, is the setting.
No windows, thank you, the tower isn't ment for looking, but if you do a WEV you can have some small windows between the roof and the wall.