The back of John Curry’s tee shirt sports a QR code, at Hacker Dojo, in Mountain View,  Calif. on Saturday, May 25, 2013.  (LiPo Ching/Bay Area News
The back of John Curry's tee shirt sports a QR code, at Hacker Dojo, in Mountain View, Calif. on Saturday, May 25, 2013. (LiPo Ching/Bay Area News Group) ( LiPo Ching )