That is why programming languages used only the first 70 or so columns of each card. The last few columns were ignored and you could punch a sequence number. If

That is why programming languages used only the first 70 or so columns of each card. The last few columns were ignored and you could punch a sequence number. If you dropped your deck of cards you could take it to a sorting machine that could rearrange them in increasing order of the sequence numbers. The trick was to make your initial sequence number increase in steps of, say, 100. Then if you later had to insert cards in the middle of the deck you could use intermediate sequence numbers. This is also why the cards had one corner sliced off - you could immediately tell if a card was upside-down or flipped over.