Hypercubical Power Source

Hypercube speaker with the enclosure made of Graphene stretched over a wire-frame rhombic dodecahedron - bet the back-wave would bend the Graphene, generating an enormously strong (300+ Tesla!) pseudomagnetic field that would interact with the electrons in a coil conveniently placed around it in a manner quite out of proportion, in terms of pure output POWER (Voltage X Current) to the power input to the voice-coil of the driver - kick-start that rig with a nine-volt battery (or a solar cell, heh, heh, heh...)hooked up to a signal generator chip set to produce 60Hz sine waves through an op-amp connected with the driver's voice-coil and one just might find one’s self with a seriously over-unity device on one’s hands… ;~))

Note: It may be possible that we only need a narrow Graphene ribbon (much less expensive) stretched over a "gap" in the five untruncated pyramidal corners of a wooden enclosure, positioned at the 60Hz "resonance plane" location in the pyramid, and have five coils positioned around those gaps (like "halos" around the pyramidal corners) to generate a LOT of 60Hz AC through interaction with the 60Hz high-intensity pseudomagnetic field produced by the sonic deformation of the Graphene ribbons stretched across the gaps. A little bit of the electrical power thus generated would be fed back into the signal generator/op-amp rig - and the rest of it, the lion's share by a wide margin, would be available for... Other uses.

A real nice gimmie here is all you have to do to make this play well with others in Europe and other regions is to simply tune the signal-generator chip to 50 Hz...

And - you could make them really small, too - in fact, the most profound  engineering challenge may be keeping the pseudomagnetic field-strength low enough to avoid vaporizing the gap-coils...