The first is the power connection (left) to the laptop, in comparison to its 2007 version (right). The new version is more stylized and streamlined:
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Secondly, compare the shape of the plug (bottom) to its 2007 version (top). More smooth, less bulky:
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These are little refinements but they’re big in overall contribution. In his opening talk at the fifth annual AllThingsDigital (AllThingsD) conference, Steve Jobs described products as packages, where certain things are emphasized and others are not. A “product portfolio” is really a portfolio of details. The simplified ends of a laptop power cord are great areas of emphasis precisely because they’re easy to ignore. They prove that size doesn’t matter in improving the details.