This article was taken from the May 2011 issue of Wired magazine. Be the first to read Wired's articles in print before they're posted online, and get your hands on loads of additional content by subscribing online.

This working computer uses bits -- of Lego. Andrew Carol created a version of Charles Babbage's Difference Engine, built entirely from plastic building blocks. Babbage planned it in the 1840s but never realised it. Carol started six years ago and drew on his 15 years' experience as a software engineer at Apple: "I would work on one adder unit, modifying it until I could get as many of the bugs out as possible," says the Cupertino-based 47-year-old. "When you get one working, you can use it everywhere in the engine." The finished iteration uses about 2,000 Lego parts but the crank-operated computer is not as powerful as Babbage's would have been. "His would have been accurately made of brass. Mine's made out of a children's plastic toy."

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