This was a great story which previously didn't hit the front page. I'm glad for the re-submit policy. I enjoyed learning about the build structure of QR codes.

This was a great story which previously didn't hit the front page. I'm glad for the re-submit policy. I enjoyed learning about the build structure of QR codes. Years ago I chose to learn how barcodes are constructed so that I could create custom barcodes for my college library. Having access to nothing more than Microsoft office, I naively decided that a whole lot of conditional formatting rules would be enough to build the thing in Excel. And I was right! But it's not a method I would recommend anyone ever attempt.