According to a filing first discovered by Geek, Samsung clearly understands the limitations that head-mounted computers will bring for input.
Violently nodding your head, poking out your tongue or shouting "OK Glass" above the roar of a subway train is all very well when no one else is around. But in public, such acts could be misinterpreted by those around you.
Samsung's take is to project an augmented reality layer on to the wearer's hands so that when he or she is wearing smart glasses and glances at their palms, just like Lady Macbeth, they see something that isn't really there.
However in this case, rather than blood, it's the keys of a keyboard. A camera in the smart glasses then tracks the movement of the wearer's thumbs as they tap the areas of their fingers where the letters appear.
As Geek points out, the fact that a patent has been filed doesn't mean that a product based on the idea is on its way, but what it does highlight is that Samsung is seriously thinking about how to overcome the biggest limitations currently facing wearable technology devices.
It also means that twiddling one's thumbs could soon become a sign of increased productivity, rather than of idleness.