parallel_prankster writes "Researchers at MIT are developing tiny robots that can assemble themselves into products and then disassemble when no longer needed. 'A heap of smart sand would be analogous to the rough block of stone that a sculptor begins with. The individual grains would pass messages back and forth and selectively attach to each other to form a three-dimensional object; the grains not necessary to build that object would simply fall away. When the object had served its purpose, it would be returned to the heap. Its constituent grains would detach from each other, becoming free to participate in the formation of a new shape.' To attach to each other, to communicate and to share power, the cubes use 'electropermanent magnets,' materials whose magnetism can be switched on and off with jolts of electricity."