QR Codes are two dimensional (2D) graphic images that encode many types of data. If you look at the image above, you will probably recognize the look, just as I am sure you can picture a bar code in your mind just by my mentioning them.
I created a video that transitions through 360 QR Codes so you can begin to see what changes, and what stays the same.
The following graphic maps the purpose of the different features of the QR Code:
Image from Wikipedia licensed under GFDL
US Patent Application drawing.
A 2007 US patent application outlines a method of decoding the QR Code. One of the benefits of the QR Code, is the Denso Wave patent is not enforced. It is effectively an open format. If this patent application is granted that would be unfortunate. Software patents impede innovation, and don’t benefit the public. If you find prior art that shows any of this method is not new or is obvious to a person trained in the art, then let the world know.