MIT's Magic Bag Of Sand

Jun 5, 2013
Originally published on June 5, 2013 10:48 am

It starts on a highway.

The camera pushes in. And there, near the meridian line, you see a faint scattering of red lights. Something is in the tar. And it's glowing.

One by one, teeny red cubes, with delicate circuitry on their sides, squeeze themselves out of the suddenly soft road and start to bounce free ...

There are thousands of them. Tens of thousands. They are rippling with energy, and they're waiting ... waiting ...

... for what seems like a command, when, all of a sudden, they start climbing frantically on top of one another, scrambling upward to form — clearly, they're becoming something ... but what?

It's a ... a ...

... a faceless avatar of evil (of course) from the movie Ra.One, a Bollywood sci-fi film starring Shah Rukh Khan.

In the movie, the cubes are little units of intelligence, magnetized and given a wee bit of energy to create the villain's body, mask and clothing. Here's the creepy scene ...

This is, of course, movie technology, something dreamed up by a screenwriter who imagined it while sitting at a cafe somewhere, far from facts, engineers and common sense — in other words, a movie fantasy.

Except it isn't! To my astonishment, there's a lab at MIT working on smart cubes, and to my double-astonishment, they look very much like the cubes in the movie, and triple-astonishing, what MIT's Daniela Rus and Kyle Gilpin plan to do with their cubes is queerer and more fantastic than the movie version. Plus, they've already started.

Here are the ingredients:

As you can see, they've got a little cube frame, some simple, foldable circuitry and a battery pack. Each cube can link, unlink and send a message to a neighbor. Right now, these cubes are about the size they were in Ra.One, the movie, but engineer Kyle Gilpin wants to make them smaller, way smaller. He wants to make what he calls "smart sand."

Here's what he imagines. You fill a bag with these little intelligent grains, and then you drop in ... oh, it could be anything — a hammer, a doll house version of a chair — and then you shake. That's all you do ... shake.

What happens is the sand gets bumped around, and eventually the little grains get wedged up against the hammer inside. The hammer is now covered, on all sides, by sand. Here's the beauty part: Each grain of sand that's touching the hammer maps its little border, and when all the grains communicate, together they create a perfect silhouette of a hammer.

And then (I should say "AND THEN!" because this is so surprising) ... Kyle Gilpin thinks he can get his bits of sand to send messages to the rest of the sand in the bag — loose sand, not near the hammer. The message is: "Copy this!" And the new grains will create a perfect copy of the hammer!

Hammer Cloning

So now we've got two hammers in blocks of sand sitting in the bag, the original and the copy, and then (no, let me say AND THEN! ... ), a command is given to "Let go!" And all of the grains that aren't being hammers fall away, leaving two distinct hammers inside in a pile of loose sand. You can then open the bag, reach in and pull out the original hammer and a perfect, sand-built copy.

Or if you like, you can put in a little hammer, and have the smart sand give you a bigger one. When you are done with the hammer, you can drop it back in the bag and give it the "Disassociate" command, and it will go back to sand.

Crazy, no? Each grain of sand has no idea what it's about to build. Nobody says to the grains, "Here's a blueprint." Instead, they tell each other.

This spring, Kyle Gilpin made a video describing the logic of his system. He used a two-dimensional drawing of a man to show how it works. So watch him here, doing (in a 2-D, very simple way) what those smart cubes did in the movie ... duplicating a man.

Right now, Daniela Rus' lab is working in two dimensions only, and they are only beginning to figure out how to downsize their cubes into sand grains. How long will that take? I figured something like 100 years — that's my normal guess for ideas that seem totally out there — but, in an interview on the Flexible Elements podcast series, Kyle Gilpin said he could imagine having a smart sand model in less than 10 years.

Really? Think of making an extra chair, wrench, plate, whatever you need whenever you need it, in a handy dandy bag of sand? Feels like a movie to me. But I don't know Kyle Gilpin. Either he's mad, or he's a very good engineer. (Or maybe he's both?)


Here's Next Media Animation's story — very short — describing the bag-of-sand concept:

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