From their paper: <a href="http:&#x2F;&#x2F;tmg-trackr.media.mit.edu&#x2F;publishedmedia&#x2F;Papers&#x2F;527-inFORM%20Dynamic%20Physical%20Affordances&#x2F;Published&#x2F;PDF" rel="nofollow">http:&#x2F;&#x2F;tmg-trackr.media.mit.edu&#x2F;publishedmedia&#x2F;Papers&#x2F;527-in...</a><p>it appears they use 900 motorized slide potentiometers connected to bowden cables.<p>Current prices from mouser suggest that the actuators alone cost $23,000. This isn&#x27;t a cheap toy, but it does show what we could do if actuators got cheap...