Black public payphones scattered occasionally in the hallways. Unlike the modern-looking school, these phones look strangely old with the black coating peeling off in places, and there is significant static when you pick up. It seems someone unknown—name, gender, and face a mystery—is always calling the school. They seem to be looking for someone, but they never show themselves first. Whenever you try to call back, it's always a non-existent number.

A rulebook containing safety and cautionary information. It seems good to check whenever you forget the guidelines. The contents are always as follows: . . . A. You are the only living being in this school. B. Please strictly observe class times. C. Even if you cannot hear what the children are saying, pretend to understand without fail. That is just how it is. D. All doors leading outside are locked.

Just an ordinary textbook from that era. Nothing particularly special about it, except that it's not a general hospital, yet a significant number of subjects are mixed together. The subject changes with every page turn, making it difficult to learn.

Oh, surely not. You aren't planning to handle this blade, are you? There, that's a good child. This object is dangerous. I'll keep it in my room. ...Depending on who is looking, a dangerous object is bound to appear. I wonder what you see?

Balloons stuck sparsely on the walls of hallways or classrooms. Whenever you aren't looking at them, they assert their presence by making the sound of popping on their own. When you go to the spot where one popped, the fragments are always nowhere to be found; they simply vanish. Well, you probably don't need to give them that much attention.

One of the teachers who will look after you! She is in charge of your classroom, quiet... faithful... and gets the job done. When she gets angry...

Medicine.