I came across a neat implementation at UTA's ARRI. There was a gizmo there called the Texas Microfactory, and it actually could assemble things on the microscale this way. I'm not sure how hard it is to get a tour of the cleanroom, and I wasn't able to find many good pictures of it easily.

Really, it was enormously impressive. That it worked, that is: turns out the magic of the system was the controls engineering. Placing manipulators on manipulators makes for a heckuva unstable system (every minor error upstream compounds, and timing starts to be everything). And if you go for stability, it becomes too slow to be useful.

But it could stack blocks in a clever way, and any microrobots that do anything at all is pretty dang impressive.