that would of course be the easiest thing to do.... No I just have noticed them before and I thought it might be neat to document them and see if I ever got 2 that were the same...and If I was ever able to identify them. I have never seen anything done on them before...but I didn't really dig that far. And as seeing how about 1 out of every 5-7 $100 bills I look has at least one (if not 3 or 4) I thought it mike make an intresting research topic