Kids in school certainly have learned the way of the classroom ever since the days of yore. And why not? They must endure the torture of lessons day in and day out. Nothing like a good screeching prank to liven things up a bit.
“OK, when the substitute walks in, everybody drag your nails down the board!”
Image courtesy of http://history.icanhascheezburger.com/2011/08/30/funny-pictures-history-hellions/.