About "Eternal engines" and patents on them:
I also have a friend who works in the patent office. They pulled him somehow a piece of cloth rotating, squeezed in the face and, like, “Patent I want.” After the question of what patent to be issued, the answer followed: "The engine is eternal!". There was a brief dialogue between (Z)Nakim and (I)inventor:

Q: What is your engine?
He hasn’t stopped here for a few months.
Q: Do you know the difference between the eternal mechanism and the eternal engine?
and :?? to
A: The engine does a useful job, i.e. It gives energy for something, and the mechanism is simply encircled in something within itself.
And (thinking) that it is a great way to drive away the flies!
Z (turning the paper in the tube): This is what perfectly drives away the flies, and even destroys them, and it is definitely enough for my life.

The inventor never appeared again and the flow of scientists sharply declined.
And I advise you, comrades readers, to remember the difference between the eternal engine and the mechanism.