The challenge for London was, "What's going to be the 'wow factor, '" said Michael Payne, the former marketing director of the International Olympic Committee and chairman of the international division of Crystal CG, a Beijing-based company that made the people-pixel graphics.

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The computer's name is generally believed to be a play on "pixel, " the smallest element of computer graphics.

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At 220 pixels-per-inch, the Retina display's pixel density is so high the human eye cannot distinguish individual pixels from a normal viewing distance, so text and graphics look incredibly sharp.

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