Something to think about:
"So I'll tell you how.
Get wire.
Take the model of the butterfly "tongue".
Wind such a spiral.
Place flat on the ground.
Place a second one, mirror image orientation, on the ground.
Connect the two at the outside ends.
Now scale the design, and wire length such that the inductance so formed becomes self reasonant at 7.83 hz.
Now add a coupling transformer in the "straight leg" between the two coils.
Now re-tune the inductance to 7.83 hz.
Attach your "load" to secondary of your transformer.
Be ready for more power than you might expect, fire, or mechanical damage to property.
Have a great day!"
https://www.godlikeproductions.com/forum1/message5302464/pg2 Search for Lost Pottawatomi
also
https://ibb.co/8D1Q332