Thank you! I've always put a bar code on the back of my cards with the numbers as part of a code. Originally, the numbers just told me the order in which I made the cards, but I've since changed it to tell me the date on which I finished them. Starting with that particular card, I've also tried to make my bar codes interesting as well. And, yes, the bar codes are all fake - they won't scan anywhere. Incidentally, that's also the first time I've drawn an armadillo.