FORTUNE — The chart above, created on an iPad, may be Horace Dediu’s the best graphical representation yet of Apple’s (AAPL) business model circa 2012. According to his footnotes, the height of the light blue rectangle representing payments to developers (Dev Payments, lower right) equals $1 billion. When zoomed in on a retina iPad, each pixel equals $50 million.
The chart has sparked a fascinating discussion at Dediu’s Asymco.com, where readers are engaged in a chick-and-egg debate about which came first, the value Apple’s iTunes content adds to the devices, or the power hundreds of millions of devices have to attract valuable content to Apple’s online store?
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