Even the palm of your hand. I don't see myself wearing one of these prototypes, but one could imagine that e.g. laptops or even mobile phones would embed these kind of new technologies. And I have trouble thinking of situations in which it is really handy to work with these kind of computers. Would doctors use it? Or other technicians to remotely guide robots? These kind of prototypes show that technology can 'disappear' and will work silently in the background guided by our gestures or speech.