Maarten Steurbaut has a page dedicated to his lego constructions, some of which are puzzle reconstructions using legos. In addition to functioning Rubik’s cubes, Maarten has also created a number of 3D jigsaw puzzles. He uses standard lego bricks and plates in combination so that all of the puzzle surfaces are smooth. It’s a method he calls SNOT (Studs Not On Top.) His site is worth a look.
