xkcd #3099: Neighbor-Source Heat Pump
Title text:
The installation of the pipes on the inside of the insulation can be challenging, especially when the neighbor could come home at any minute.
Transcript:
Transcript will show once it’s been added to explainxkcd.com
Source: https://xkcd.com/3099/
Fantastic! The actual perpetual motion machine has finally been found. And all this time, I thought it would need magnets, which are also magical. But I guess all those motors in the heat pumps use magnets too.