This Modulex® mosaic is made from studless bricks (except for the border). The size is 39 x 39 studs (14.5 cm square). This is the QR code for my website. I plan to bring it along for my vendor displays at conventions. It works great! There are many QR code readers for smart phones (many are free). I had been using QuickMark for my iPhone but just started to use OptiScan (was given a promo code to try the app) and I like it very much (seems to be much quicker at scanning).
Contact me if you would like to commission a custom QR for your own website.