"Invincible" is a science fiction novel by Stanislav Lem.
On the desert and uninhabited planet Regis-III landed the second class cruiser "Invincible". Shortly before that, another terrestrial ship, the Condor, disappeared from this planet, having sent only two messages before that. The first was about a successful landing on the surface of the planet Regis-III, and the second - about some "flies". The biologist Lauda speculates that the planet is evolving mechanisms left over from an extraterrestrial civilization that came from somewhere in the constellation Lyra.
Judging by the few traces preserved from the first colonies of robots, their types there were several. "Mobile" - mobile work, complex, intelligent, armed, powered by nuclear energy. The "simplest" are capable of limited adaptation, but they did not depend on the availability of spare parts and radioactive fuel. Their evolution has led to the survival of the fittest. And such were the simplest works. With their distant descendants, who look like "flies", and faced the expeditions of the earthlings…
