Everyone has seen a barcode, a little strip of lines that represents a simple alphanumeric code, typically used for keeping track of stock items. There had been no need to improve on this for a long time.
Back in 1994 the Japanese wanted a better code to keep track of their cars and they came up with the two-dimensional QR-Code. These days they are popping up everywhere. A square that looks like a mass of random black squares _ there should be one near this column. The three larger squares at the corners are for position and the smaller offset one is for alignment. The code also contains version, format and timing elements and incorporates data and error correction.
Anyone with a smartphone can download an app that will read and display the content of a QR-Code that can hold a lot of information e.g. over 4,000 normal characters. If you scan the example here you will find a URL, the most common usage these days. I won't spoil the surprise so give it a go.
This article is older than 60 days, which we reserve for our premium members only.You can subscribe to our premium member subscription, here.