What makes a product a design classic -- a gadget, tool, vehicle, or furnishing that stays in production for decades, constantly reaping revenues? Editors at London's Phaidon Press have come up with a definition that might surprise you: a commercial object that uses innovative, new materials or cutting-edge technology, united with a timeless, simple form. In other words, most of today's design classics were yesterday's radical experiments. Of course, to truly earn "classic" status, they've also had to withstand the test of time, staying true to original lines and shapes through various incarnations. From a 120-year-old whistle to the iPod, here's a list of 10 timeless examples from the recently published, three-volume reference, Phaidon Design Classics.