# Dan Hollick - QR Codes (Highlights) ![rw-book-cover|256](https://readwise-assets.s3.amazonaws.com/static/images/article2.74d541386bbf.png) ## Highlights - When a mask is applied to the code anything that falls under the dark part of the mask is inverted. A white area becomes black and black area becomes white. ([View Highlight](https://instapaper.com/read/1543428787/20907517)) ^394249669 - Perhaps the coolest thing about QR codes is that Denso Wave, the company that invented them, never exercised their patent and released the technology for free! ([View Highlight](https://instapaper.com/read/1543428787/20907524)) ^394249670 Respect