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.
-- Douglas Adams, The Hitchhiker's Guide to the Galaxy, ch. 11, 1979.
"Rather than bending down, leaning forward or picking it up you can use larger movements a little bit further away to do things like volume up or next song without changing modality.”
-- Stian Aldrin, CEO of Elliptic Labs, quoted in Kinect-like technology for iPad to wave through CES, Fabrizio Pilato, Mobile Magazine, 21 December 2010.
(I haven't touched SaVi at all this Christmas.)