Several companies are working on eye-tracking tech as a way to navigate devices. A team of MIT researchers, however, have their eyes set on another body part: the thumbnail. Graduate students Cindy Hsin-Liu Kao and Artem Dementyev are developing a tiny trackpad that fits over your thumbnail. They're calling it NailO, and it was inspired by colorful nail stickers popular in Kao's native Taiwan and many other Asian countries. The duo envisions NailO to be used in situations where both your hands are occupied -- for instance, you can use it to scroll down a website page to check recipes while cooking. They also think it could be used to control other wearables, such as smart jewelry.