Swans on Tea

“Eddies,” said Ford, “in the space-time continuum.”
“Ah,” nodded Arthur, “is he. Is he.”

Everyday Electromagnetism

This time, though, Eddies in the penny. And he enforces Lenz’s law.

You can see a similar effect if you drop a magnet down a copper pipe, because the eddy currents will flow, and the induced field is such that it opposes the acceleration, so you get braking.

If you want to be more practical, instead of moving the magnet you could move the copper around, cyclically, and tap into the current that would flow. Just a thought.