Those notches are about to turn 50! There's a lot of patents out there for various hand alignment helpers but the one that is closest to what everyone is used t

Those notches are about to turn 50! There's a lot of patents out there for various hand alignment helpers but the one that is closest to what everyone is used to is 3848723 [1] filed 23 July 1973. [1,pdf]: https://image-ppubs.uspto.gov/dirsearch-public/print/downloadPdf/3848723 https://image-ppubs.uspto.gov/dirsearch-public/print/downloa...