Speaking of rulers the boys asked me the other day why it was that when I draw a line, using a ruler, I always turn the ruler over so that the bevelled edge is resting on the paper.
"Habit" I replied "All due to having to use a pen and ink at school, if you don't turn the ruler over then the ink will smudge"
Being used to pencils and ball point pens they were baffled.
My how times have changed. Made me feel even older than I am.