In touch-based computer interfaces, the touching only goes one-way: you can tap and swipe and pinch the objects onscreen, but since they aren't physical, you get no tactile feedback. A team of designers at MIT Media Lab's "Tangible Media group" are trying to rectify this with their Recompose concept, an experimental computer input device that's part keyboard, part gestural interface, and part 3D display surface. Trust us, it'll all make sense after you watch the video:
Formally, the team describes Recompose as "direct and gestural interaction with an actuated surface." Basically, it's a touch-based interface that touches back, using physical tiles (like the keys on a keyboard) mounted on little pedestals that can rise or sink based on direct input (ie, pushing them like buttons) or gestural input (waving your hands over them like a Jedi master).
But the extra bit of genius in Recompose is its third purpose as a display device. Actuators in the tiles can provide force-feedback to your fingers to "display" tactile information about your data (this could be useful for CAD designs or sophisticated maps or scientific visualizations). Plus, since it's literally a grid of physical objects, it can display information visually by morphing its own topography in 3D. Bar charts just got way more awesome.
In true MIT-hacker manner, Recompose is built on the back of another Media Lab innovation, the Relief table -- an "actuated tabletop display" which provides the 120 motorized tiles. Maybe next they'll combine Recompose with the video capabilities of Microsoft Surface, and really blow our minds...