I remember a few years back, the exact opposite thing happened. At my middle school, they had this stupid system of splitting up third period into thirds (the first before lunch, and the last two after), and my math class just happened to fall under that. The math teacher finished his topic, and couldn't go on because of time constraints, so we had about five minutes to wait until we left for lunch. Some kid had the brilliant idea of tapping his pencil on the desk. Then, someone else did the same to a different rhythm. And someone else, and so on and so forth until most people in the class were doing it. The whole time, the teacher was sitting at his desk, ignoring this until he dismissed us.
