(Pocket-lint) - Google Maps could be about to be covered with adverts following a Facebook HQ stunt that has seen the social network's headquarters roof get a massive 42ft square QR code.

The code, which loads your mobile phone's browser with a URL when you scan it with a QR reader on your phone, was created as part of the "Space Hackathon" to decorate Facebook's new headquarters in Silicon Valley in California.

Although employees where supposed to worry only about decorating the rooms they work in, Mike Pike took it a little bit further and painted - with the help of 30 colleagues - the large interactive barcode on the roof of the building.

At the moment it is visible only on the handful of images that have been taken by aerial photographers, but it won't be long before it starts to appear on services like Google Maps or Bing.

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That's led us to believe that Facebook could have accidently started a new advertising craze that could mean Google Maps is covered in adverts in the future, and that companies could advertise on the mapping sites for free if they are willing to paint their roofs.

Scanning the Facebook HQ QR code currently loads fbco.de (FB Code), which details a "coming soon" icon, however Pike has said that he would like it to be a place to RickRoll people or share ideas.

We can easily see others following suit, and where there were once just empty roofs, soon there will be lots of information to capture and scan.

Writing by Stuart Miles.