There is this guy in the garage, playing with magnets and coils, finds something strange. He put together this wheel, turned the magnets just right, and and the wheel keeps on spinning. He shows it to his engineering friend, the guy tells him that he made a mistake, it is not perpetuum mobile. So he builds a bigger one and connects a light bulb to it. The bigger wheel keeps on spinning, and the bulb makes light. He shows it to a dozen people, they tell him that he is cheating and this is impossible. The guy sells his house, builds a 100 meter diameter wheel from the money, connects an induction smelter to the output. Shows it to thousand people, he keeps smelting cars down and the smelter gets warmer and warmer.
Everyone claps their hand, that it is a nice trick, they go home. The guy is devastated. I cannot prove to these people that my perpetuum mobile works. So he walks to the lever to switch it off. The lever is stuck, too much current. The wheel keeps turning and turning, and the smeltery gets warmer and warmer...
10000 light-years away there are two guys in an astronomic observatory, looking at the screen. One of the guys points at a white blob with all his 4 hands, saying:
"Hey look, a supernova. It wasn't there yesterday."
"Well, there goes another civilization, which didn't realize that wishful thinking can violate the laws of physics."
He takes a sip from his coffee and writes down the time and date into a notebook.