An overview of Ceilingmansion, what there is of it so far (I'm barely into Year 7 at the moment...)
The northeastern arm of the Ceilingmansion.
At the top you can see the 2 z-layer cistern under construction. Beneath that is a barracks room and a drowning chamber (not the same room... the drowning chamber is the section of the bottom floor that is NOT fortifications (the light-colored walls)).
Also visible in the distance are two pillboxes that have come in quite handy in sieges, the end of the north arm, and the current main entrance. That structure at the main entrance is full of traps and 20 chained war dogs.
The pump line for filling the northeast cistern.
There will eventually be a line of 25 pumps connecting the northeast cistern to the center of the map.
The barracks level of the north arm, with the cistern sliced off.
Note the columns in the middle to allow water to flow neatly from the cistern to the drowning chamber.
The north arm of Ceilingmansion (well, half of it...)
The distance from the support pillar (right side of picture) to the northern entrance (left side) is one-quarter of the full width of Ceilingmansion. When it is completed, there will be a ring around the entire outer edge of the mansion (for now, I'm working on the inner ring.) The east and west arms will stretch to as far as constructions can possibly be built on a 5-wide embark location (it's 5x7, so it doesn't work the same in the vertical direction).
With the sole exception of the drowning chambers, the entire first floor is and will be fortifications. Also, the entire aboveground part of the structure is made completely of blocks. (Chalk for the first floor, obsidian for the next two so far.) Eventually, there will be an immense dining room (with statue gardens on each arm) above the waterworks level (I'm thinking I might even put in a mist waterfall or four). Above THAT, will be residential areas, followed by nobles' quarters. At the very top will be the King's throne room.