Haha :) that is very nostalgic. I had friends who would mark on their textbooks, their pencils touching the page with the lightness of a feather, only when it was utmost necessary and then erased it off at a later point. Might I mention that they erased from a single predetermined corner of the eraser, leaving the rest of it pristine. I, of course doodled and wrote all over the place. Needless to say, I was an outcast among my friends for doing this ;)