after reading this thread, i had 2 exams the next day. there were so many opportunities to do things like this!
it was hard to resist, so i settled with something much less obvious.
there was a Chemistry question about 2 bottles of water: MOUNTAIN SPRING and SOURCE. i couldn't resist to add a Y on the end of the word SOURCE, and now that i think about it, it was a fairly big Y..... might get into a bit of trouble, especially if i couldn't answer the damn question too!
BM