Strangely, punched cards are just a bit bigger than the old US currency, not exactly the same size. Also strange: nobody knows exactly how big the old currency

Strangely, punched cards are just a bit bigger than the old US currency, not exactly the same size. Also strange: nobody knows exactly how big the old currency was. To be precise, there are three slightly different sizes quoted as the official size. I asked the Bureau of Engraving and Printing about this - they print the money so they should know - and they couldn't explain the discrepancy.