Douglas Adams made fun of the idea of gesture interfaces in his 1979 novel Hitchhiker’s Guide to the Galaxy:

“A loud clatter of gunk music flooded through the Heart of Gold cabin as Zaphod searched the sub-etha radio wave bands for news of himself. The machine was rather difficult to operate. For years radios had been operated by means of pressing buttons and turning dials; then as the technology became more sophisticated the controls were made touch-sensitive–you merely had to brush the panels with your fingers; now all you had to do was wave your hand in the general direction of the components and hope. It saved a lot of muscular expenditure, of course, but meant that you had to sit infuriatingly still if you wanted to keep listening to the same program.”

But wouldn’t it be a game changer if you could buy a Snickers without physically touching the button? Can your ring tell the machine to rock back and forth when the candy gets jammed?