I'd be lying if I said I understood at all how these worked.
The first thing I saw on TV about 3D printers made no sense to me and I was certain at the time that I was seeing someone's April Fool's gag at the time.
Clearly, they exist, but my brain can't grasp that we're that far forward at this point.
I feel bad for the folks at Grandt Line and places like that because their days are clearly numbered.