QR code (via wiki)
QR codes have been placed on just about everything since their inception by Toyota’s Denso Wave subsidiary back in 1994. Back then the idea was developed to help the company keep track of manufactured car parts. We can find them on everything from newspapers to every kind of packaging known to man. The codes are able to hold an incredible amount of information (compared to bar codes) which is stored using data in one of four modes such as numeric, alphanumeric, binary or Kanji (logographic Chinese characters). Up to 3kb of 8bit data can be stored in a QR code (That's 7,089 numeric or 4,296 alphanumeric characters).
Besides commercial tracking, entertainment and marketing (to name a few) QR codes might find their way onto currency as yet another form of protection against counterfeiting. Researchers from the University of South Dakota and South Dakota School of Mines and Technology, led by Jeevan Meruga, have designed a process that allows a unique invisible QR code to be integrated into paper currency. This could be used as a deterrence against those who have a career in the ‘funny money’ business.
The team designed their code using CAD to generate a random QR code, which can then be applied to currency using an aerosol-jet printer. The ‘ink’ used is what makes the code unique and is made from small nano-particles combined with blue and green fluorescent dyes, which can only be seen using near-infrared light. The codes generated using this technique can range all the way down to macroscopic levels in size. The ink itself is robust enough to be used in future generations of paper money. This isn’t the first time the thought of using QR codes on currency has been considered as the Royal Dutch Mint released the world’s first coin with a QR code embedded on it in 2011. How long with this technique keep counterfitters at bay? I'd say a few days after it is introduced.
Kraay Family Farm QR code (via Kraay)
In contrast to the tiny invisible QR code, the world’s largest (as of 2012) would belong to the Kraay Family Farm in Alberta, Canada. The largest QR code is actually the farm’s latest corn-maze design and covers around 309,570ft according to Guinness World Records. The amazing part of the maze is that you can actually scan it using your smartphone (or other mobile device), which takes you to the farm’s website! However in order to do so you have to fly over it, but intergalactic aliens should have no trouble in finding some fall produce (to accompany their human meals and crop circles). Talk about advertising.