Could 3D objects be printed from a distance? Say, by pointing a laser at a stone wall?
I'm not concerned with whether the requisite technology already exists or would be difficult to build, but rather, whether something like this could be built in principle, or if there is either a law of physics or a massive intractability that would prevent it.
If it is possible, I'm interested in the theoretical limits. How far away can the material be (e.g. can we print something on the moon with a laser stationed on earth)? Can any material be used? Etc.