The place where something like that would be most useful would have to a pen-based computer of some kind, perhaps a tablet computer, or other walk-around device.

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The FLY, for lack of a better description, is essentially a pen-based computer for kids that lets you write stuff down on paper and then interact with your drawings.

ENGADGET: LeapFrog's FLY pentop computer

Apple itself launched a pen-based tablet computer, the Newton, in 1993, but it was a flop.

ECONOMIST: Tablet computing

Rossman, a former Apple Computer executive who also headed the failed pen-based company Eo, owns 3.5 million Phone.com shares.

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