Comment by devmor

I suppose if we’re assuming that overturning thermodynamics is the byline, such a machine could exist without being a perpetual motion machine if somehow the energy that produces the machine’s work was lost as say… nuclear radiation instead of heat?

Or perhaps requiring some kind of catalyst that is rendered into a higher energy state which is functionally useless for its purpose as said catalyst?

Either way, we’ve got some interesting sci-fi concepts to work with!