Apple today filed for a US patent on a “bi-stable spring with flexible display,” which looks awfully like a watch. We already knew the company has a team of 100 people working on a so-called iWatch, so the patent application deserves a little more credence than we might ordinarily give it. And with Google this week more aggressively marketing its augmented-reality eyewear, Google Glass, wearable computing is starting to look like more than a fad.