Make Your Own World With Programmable Matter - IEEE Spectrum

Make Your Own World With Programmable Matter - IEEE Spectrum: Goldstein and his colleagues think that an efficient way to produce shape changes might be to fill the initial blob of catoms with lots of little voids and then shift them around to achieve the right contours. Small local movements of adjacent catoms would be sufficient to shift the cavities, and if they are allowed to bubble to the surface, the overall volume would shrink. Conversely, the material could expand by opening up pockets at the surface and engulfing them.