Why do QR codes have squares in three corners?

 Even if you've never heard of a QR (Quick Response) code, chances are that you're already subconsciously familiar with them.

The idea behind a QR code is to create an image that can be scanned by any modern day Smartphone (with a QR code reader application) and translated into something more meaningful. QR codes are often used to contain web address information and links, but they can be used to direct Smartphone users to a multitude of other media too (e.g. videos, images etc).

Basically, a QR code works in the same way as a barcode at the supermarket. Every QR code consists of a number of black squares and dots which represent certain pieces of information. When your Smartphone scans this code, it translate that information into something that can be easily understand by humans.

1. Quiet zone: An empty white border that makes it possible to isolate the code from among other printed information (for example, on a dirty envelope, among the black and white print of a newspaper, or on smudged product packaging).
2. Finder patterns: Large black and white squares in three of the corners make it easy to confirm that this is a QR code (and not, say, an Aztec code). Since there are only three of them, it's immediately obvious which way up the code is and which angle it's pointing at (unless the code is partly obscured or damaged in some way).
3. Alignment pattern: This ensures the code can be deciphered even if it's distorted (viewed at an angle, printed on a curved surface, and so on).
4. Timing pattern: This runs horizontally and vertically between the three finder patterns and consists of alternate black and white squares. The timing pattern makes it easy to identify the individual data cells within a QR code and is especially useful when the code is damaged or distorted.
5. Version information: There are various different versions of the QR code standard; the version information (positioned near two of the finder patterns) simply identifies which one is being used in a particular code.
6. Data cells: Each individual black or white square that's not part of one of the standard features (the timing, alignment, and other patterns) contains some of the actual data in the code.

How to Make A QR Code:-

Besides smartphone apps, there are many websites dedicated to creating QR codes with varying feature sets and levels of access without registering or paying. In most instances, you simply enter information into the relevant fields and save the QR code in a file such as JPG or PNG.

QR Code Generator is completely free and includes support for plain text, URLs, as well as contact information and the ability to send SMS messages through the QR code. You can include information in all of the fields, though again, crows more data results in more squares and makes it increasingly difficult for scanners to read the code.

QRStuff.com offers additional features such as the ability to link app stores, social media including Facebook (pages and likes), Instagram and LinkedIn, links to Dropbox files or folders, Google Map locations, Wi-Fi logins as well as shortcuts to send funds over PayPal and Bitcoin. However, if you want access to all of the site's features, namely the style/image editor, you'll have to pay.