Curious Reader! You may have to hear that someone has finally invented a perpetual motion machine. Let this rumor not plunge you into despondency. Know that even this, neglecting the law of conservation of energy, sometimes believe, as our ancestors believed in the "bad eye." On faith, and only on it, miracles of all eras and peoples hold. If doubts overcome you, do not resort to another extreme - the arguments of Chekhov's hero, who in his "Letter to a Scientific Neighbor" proclaimed: "This cannot be, because it can never be." Better look back at the physics textbook.