Square in action

By RUSSELL A. DANIELS/The Associated Press

December 31, 2009 | 12:01 a.m. CST

Willo O'Brien demonstrates Square on her iPhone in San Francisco. Using a Square is pretty simple. Swipe a credit card through a slit on the cube's side and it will read your credit card number, translate it into an audio signal and send it onto the iPhone, where it is encrypted.

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