It is a variable setting for each code. Here's a damaged but readable QR code: https://en.wikipedia.org/wiki/QR_code#/media/File:QR_Code_Damaged.jpg https://en.

It is a variable setting for each code. Here's a damaged but readable QR code: https://en.wikipedia.org/wiki/QR_code#/media/File:QR_Code_Damaged.jpg https://en.wikipedia.org/wiki/QR_code#/media/File:QR_Code_Da...