[And that's just the obvious stuff. The click wheel on the front had to be reinvented to fit the Nano's ridiculously slim 6.9-mm profile. Ditto the battery and chips.] We use every fraction of a millimeter of space to get things in there, ... It's like a puzzle to fit all that stuff together. It has the tightest tolerances of anything we've ever made in the history of this company.

Phil Schiller