A 3D Lego Fabricator Made of Lego

eldavojohn writes "Making a Lego printer is pretty cool if you've never seen The LegoMakerBot. The creator has instructions on his site on how to make (out of Lego bricks) a machine that 'prints' Lego models — much like a 3D fabrication machine — after you model them in MLCad. The sped up video is nothing short of impressive."

Comments

Re:Physical recursion!

[hey!]

Actually, this reminds me of the classic AI simulation program "Blocks World", which *was* written in Lisp.

Basically, it modeled a group of stacked blocks, and you could tell it, "put the red block on the blue block." If there were a yellow block on top of the red block, it would figure out that in order to meet its goal of picking up the red block, it had to remove the yellow one first.

What was especially cool is it could explain itself. You could ask "Why did you move the yellow block?" and it would say "To get at the red block." If you asked "Why did you move the red block" it would say "Because you told me."

That doesn't seem like much today, but thirty years ago it was the next thing to wizardry. Once you figured out how the program worked, you really understood why recursion is such a big deal in AI programs. Each individual inductive step was simple, but the results were impressive.

To actually get the lego machine to fabricate parts is no big deal; that's just running through a predefined set of motions. What would be cool is if, like Blocks World, you told it what you wanted, and it took care of the details for you.