T.J. Rice. Courtesy of the Library of Congress For much of their history, Americans dealt with racial differences by drawing a strict line between white people and black people. But Daniel J.

And that is how the scanning of barcodes became ... which rather than using vertical lines consist of constellations of tiny black and white squares in a pattern that is readable by digital ...

It was a Thursday morning when the first unique sticker of white and black lines facilitated the purchase ... one of the first 10 scanners used to scan bar codes at the supermarket.