Adrian Bowyer thinks that Marx got it only half right: The means of production shouldn't just be seized, they should be shared by all. To that end, Bowyer, a mechanical engineer from the University of Bath, in England, has realized one of technology's holy grails-a machine that can replicate itself.In 2005, he began work on RepRap, a device that extrudes layers of plastic to create physical objects from digital designs. In addition to forging a seemingly infinite number of useful items, RepRap can make almost all of the parts for a working "child" version of itself, a feat first accomplished this May. With RepRap, the thinking goes, you can print yourself a pair of shoes of your own design, and then you can print your friend a RepRap of her own, generating wealth almost from thin air (the plastic it extrudes costs about $10 a pound). "My ambition is to allow people to have the freedom to make anything they want for themselves," without corporate industry intervening, says Bowyer. "Why shouldn't people run their own factory?"