A man of great magnetism

Chances are, you are reading these words in some room or other. Build a wall down the middle of it, and in the middle of the wall, insert a tiny shutter. Conjure up a tiny critter who can open and shut this little door at will. When a hotter-than-average air molecule careers towards it, the creature opens the shutter and lets the molecule pass to the other side of the room. Colder-than-average molecules are allowed to pass in the other direction. Soon enough, one half of the room is sweltering, while the other half is distinctly nippy. Magic?

Not yet. A fridge performs exactly this trick, pumping heat out of its interior through that dinky radiator at the back. The refrigerator only becomes magical if it carries on running after you unplug it. Fighting entropy is expensive. It takes energy. Us living types cock a spectacular snook at the forces of entropy, but we too are in a sense plugged in.