Escape from Classroom

This game is a game to escape from one classroom.
The classroom is not very big, but many hints are hidden.
Also, up to 3 classmates will visit over time.
Find items, reason, and escape from the classroom!

Up to 3 students will visit over time. However, I can not see the figure of the students. I can not see my figure from the students. But you can hear what you are talking about.
After a certain time, it will return to the time when the game started. Return many times, let's deduce the mystery of this classroom!