Right now, most consumergrade 3D printers use ABS plastic as their primary building material; ABS is the
material that makes up Lego bricks, but it's relatively brittle, which limits what you can do with it. You can expect
to see moreversatile 3D printers come to market in the not-too-distant future. And 3D printers will become
considerably more precise: The new Replicator 2 from MakerBot, for instance, can lay down layers of plastic
that are 100 microns thick - about as thick as a sheet of paper. The thinner the layers, the better the result