It is cable used to make trafo's and coils, lackered wire.
Twisted to get low capacitance and inductance.
The number of wires and the radius has some influence on the sound so I made a mix that sounded neutral.
I think it is the same idea as your's Scroobius, but electrically and estetically more correct.
BTW. The double coax I use now for the 220V from wallplug to stereo.
Not reversed but both neutral and life inside and the screen connected to the central city heating.
Wires close to it don't pick up the hum and the amps don't get RFI from the mains.
Of course sounds very good as always with DIY.
Could also be a good method for the earth wire as a third coax, should have very low resistance at high frequencies.