This is an example of what we had to endure in two year of Hell, apart from the torture.
A particularly enthusiastic Math teacher left behind in his wake, a blackboard full of strange symbols. Or atleast that's what it appeared to me to be. The next teacher walked in, looked at the board and waited for a few minutes while some losers were copying down whatever was on the board. Then cheerfully he asked,"If you don't have mind, can I rub the board?" There was a stunned silence followed by loud giggles. From both students and the teacher for some reason.