A vast corn maze is the world's largest Quick Response code - and if you happen to  overfly it you can discover that it works.  Have QR codes finally found the field they were invented for?

QR codes are the two-dimensional barcodes that you can scan with a smartphone to access information on a website. They are typically measured in square inches or square centimetres. Those in magazine adverts or on packaging are often as small as 2.25 square centimetres (0.4 square inches) while those in windows displays or on gravestones might be 100 square centimetres (16 square inches).

The one photographed here measures 29,000 square metres (309,570 square feet) and is officially the largest yet, according to Guinness World Record.  

It is to be found in Alberta, Canada as one of the visitor attractions at the Kraay Family Farm which constructs a new maze on an annual basis.

The idea was seeded (pun intended) by noticing how a QR code on a magazine cover resembled a maze (pun not intended) and then was transformed by growing maize.

To make the design into a functional QR code the earth background had to be made darker but if you scan it from a passing aircraft you will go to the Kraay Family Farm website - and scanning a photo of it also works.

For many this impressive construction simply demonstrates the basic flaw with all QR codes - they are simply more trouble to scan in than typing in a URL.