My cousin, Jarren, designs things in 3 dimensions. He redesigns tools and bolts and other things that need to be improved. I never knew about the 3-D printer. My aunt sent this to me and it is really interesting! The guy recreates a wrench and the 3D version is a useable tool.
This is worth watching.
This is the most amazing thing you will see today!
http://www.youtube.com/watch?v=ZboxMsSz5Aw