They look like miniature magic eye illusions; an indistinct pattern of perpendicular black lines, their borders forming a square. Quick Response (QR) codes are becoming increasingly popular. In essence all these lines are is a block of information that can be read by the majority of smart phones by taking a picture of the block.
We have started using QR blocks for two main reasons. The first of these is that the block can fire your internet browser and open the relevant campaign page, taking you straight to a source that can provide much more detail than could be fitted on a leaflet, poster, billboard or adshell. The second of these is the ability to tie these to SMS systems. A text message can be automatically sent with more information and even used to create a subscription to service updates. Alternatively they can be used as a quick way for taking contact details.