CHICAGO — Are they black-and-white bathroom tiles? Newfangled bar codes? Postage stamps honoring artist M.C. Escher? Thanks to increasingly prevalent smartphones, many marketers and organizations are ...

Among the many changes brought about by the pandemic is the widespread use of QR codes, graphical representations of digital data that can be printed and later scanned by a smartphone or other device.

QR (quick response) codes have been around for nearly 30 years. Developed in 1994 by a Japanese engineer for the purpose of tracking components in car factories, they have evolved into a highly ...