It’s been a full year since Lenovo announced it had signed up Ashton Kutcher as a “product engineer,” and Lenovo is apparently happy with the partnership. The actor/investor is to appear via satellite at a Lenovo event in London on Thursday to introduce several new products, including the new Yoga 3 Pro and ThinkPad Yoga 14 notebooks. (Two new Android Yoga tablets were also announced.) Moving parts are usually the first things to break on a computer, so conventional wisdom is the fewer, the better—especially on a notebook that must withstand the rigors of travel.That renders the hinge design Lenovo’s engineers have come up with (I can't imagine Kutcher had much to do with this) as audacious as it is beautiful. Dubbed the “watchband” hinge, it consists of more than 800 individual pieces of steel and aluminum. Metal watchbands are pretty durable, so maybe the 800 pieces of steel and aluminum that comprise the Yoga 3 Pro's "watchband" hinge will st...