In the future, everything could become a touch-sensitive interface, but it wouldn't be the object itself that was picking up the movement, it would be a system integrated into each finger, specifically under the nail. It wouldn't cost much either, all you need s a basic web cam and computer.
This would allow anything to become touch-sensitive, like the rock seen in the video.
The touch sensitive nail system developed at University of Nottingham, UK uses a camera under the surface of the finger which monitors the blood flowing beneath the nail. It does so by tracking colour changes in the skin.
Try it. Press your finger against anything around you and observe as the skin under your nail gets paler. The reason that happens is because the blood goes to the base of your finger which goes darker. Try it against a piece of glass to see for yourself. The contrast will vary depending on how much pressure is being used.
"When you touch a surface, even lightly, the blood under the nail concentrates in one place. Surprisingly, this is relatively easy to spot with a camera," says Joe Marshall, one of the project researchers.
Like the video shows, anything could become touch sensitive.
"It was presented as 'my pet rock' and people seemed to really engage with that," he says. "One person actually asked me if they could take it home."
So that's the theory anyway, but my finger goes white underneath when I press things, so I don't know. Then again, I could just be strange.