QRcodes give advertisers the opportunities to be creative in the ‘noise’ through minimising the data enclosed (for instance using a URL shortener) and careful positioning of the data within the square.
Swiss luxury watch brand Jaeger LeCoultre uses some carefully placed watch components in their QRcode and the complexity of QRcodes to human eyes (rather like the visual complexity of a watch movement). It was a subtle understated modification of a QRcode that fitted right in with the brand.
Want to build a creative QRcode? QArt Coder is a good place to start