The Atelier Tower

The Atelier Tower is a strange structure that appeared on Kamone Gakuen during the Picture Perfect Arc. It is also where Shijima Mei seems to reside during the arc. The students of the Picture Perfect world seem to believe it's a normal building under construction, though they don't know what purpose it's going to serve.

Locations
From the outside the atelier tower looks like an extremely tall building with different types of small rooms. It seems very structurally dangerous and absurd, and likely couldn't exist in the real world outside of the Picture. The inside of the tower has a lot more space than it looks like from the outside.

The Entrance
The Entrance room to the atelier tower seems to be huge, high ceiling room that functions as an art museum. There are lots of paintings on the walls, most of which are potraits of humans. One of the potraits is of Shijima Mei, from which she seems to mysteriously appear when Nene and Kou enter the room. The room has a long carpet in the middle, surrounded by stanchions. The floor has a lattice pattern, and the walls are adorned with paneling at the bottom. The room is very decorated, with columns, friezes, pediments and such. There are also windows high on the ceilings, which have a lattice pattern on top of them. The room also seems to have a reception table and an info kiosk.

The Art Studio
Inside the atelier tower, there is a room where Shijima creates most of her art. The room is filled to the brim with easel, most of which already have paintings on them. The studio also has a drawer with paintings of all the people in the Picture Perfect world, along with a desk full of art supplies. The room also seems to have a big, round balcony with a fence around it. The floor of the studio has the same lattice patterns as the entrance room.

The Prison Cells
The atelier tower has a strange room with cells that look like they belong to a prison. The cells have a round, barred entrance along with brick walls and floor. Inside of the cell where Yashiro Nene resided for a brief period of time, there was a big window, a chair, some art supplies and a canopy bed with a pillow and a blanket.