QR codes are here. Barcodes should be very afraid. In 1992, on a factory floor in a Toyota auto-parts subsidiary in Japan, workers were drowning in barcodes. They were everywhere: some components on the line needed ten barcodes just to capture all the tracking data. Employees scanned them, one by one, hundreds of times a day. Masahiro Hara, an engineer on the barcodes team at Denso, the subsidiary, tackled the problem. What if, he reasoned, you could build a barcode in two dimensions instead of ...