AlamyThe barcodes that appear on almost every product bought and sold in shops around the world were born 75 years ago on a beach in Miami (Credit: Alamy)Few people think twice about the barcodes on their shopping, but in the 75 years since they were first dreamed up, they have helped save lives, gone into space and stoked fears of the Antichrist.Lasers. That's what supermarket staff need, insisted Paul McEnroe. Scanners in the checkout and little pistol-shaped laser guns, too. Point, shoot, sel...