Ya, but could you build the United States Patent and Trademark Office with it?
The NYTimes has an interesting piece today on Lego, intellectual property, and competitors like Mega Bloks and Best-Lock. Of note: Lego's redirecting their IP team away from patents (theirs ran out in 1978) and over to trademarks. Bonus tidbit: "Lego did not develop the idea of plastic blocks that lock together with small knobs. The blocks were invented and then patented in 1939 in England by Harry Fisher Page, who went on to found Kiddicraft, an early maker of plastic toys."