Self-Replicating Factories: Macro to Nano

Christopher Thomas writes "A common theme in science fiction is the "replicator"; a device that can build anything on demand. An extension of this idea is the self-replicating factory, that grows in size geometrically to produce goods or to terraform hostile environments. It turns out that both of these miraculous devices are closer than they seem - in fact, to some extent they're already here. I've posted an article summarizing things."