( Techcrunch reports [link] : http://techcrunch.com/2012/03/25/facebook-rooftop-qr-code/ ) When Mark Zuckerberg called for a “Space Hackathon” to decorate Facebook’s massive new headquarters at 1 Hacker Way, he probably didn’t expect employees to take him so literally. A few scurried up to the roof with some tar paint, and now there’s a 42-foot wide QR code on the roof that’s visible […]