I believe that's standard lamp cord from the looks of it. Bifilar of course.
honestly, i cant be sure. not enough to say i believe....
to say it is bifilar is possible. with so few turns, even if all of those windings we see are in series, the freq of resonance would be way high for. a transformer/inductor with such, lets say, not so tight core configuration in my opinion.
now, maybe there could be an effect involving bucking that may enhance the bifilars effect. we see many examples of ideas that suggest setups that the resonant ring gains amplitude on its own once started, holy grail, but none that describe really how to... only diagrams that show this resonant gain in amplitude in graphs. i havnt been able to acomplish that, but have seen these subtle claims for many years now.
if the gain funtion was discovered in an audio amp power transformer(incorrectly wound at factory) or something that involved a crt yolk, then id have to say that bifilar was not a gain function ingredient. if it was something to do with speakers, quadraphonic development, maybe there were voice coils that were experimentally wound bifilar and some effect was found there, but all dual voice coils ive seen were 2 layers, not bifi as we know them.
if it was something to do with quadraphonic developement that brought on the idea, id have to say there was a gain seen in the audio output where the sound waves combined in space, similar or exactly the way i described a gain function by multiplying the number of drivers and sticking with the same power input for each multiple test. i see no speakers here, so maybe he had wisdom to apply this to a solidstate configuration.
either way, i believe the many ideas of how the tpu worked over all these years were way off base and way over complicated, either on purpose

, or just wishfull thinking...
im in the belief as of now it is all just much simpler. if you look at my 3d representation again, imagine the lower ring windings set up for a bucking configuration. all of them driven at once via pulse. those bucking sections of that lower ring have a path back through the square cores and the upper ring. this example of the tpu we are looking at is the only one that shows the most. the other tpus, larger ones, the same configuration is most likely hidden within all the black tape and maybe shape formers to give one other ideas of whats going on. totally possible.
one thing that has me going with the multiple driver gain theory is the fact that there are 4 separate windings on the bottom ring, not just 1 or even 2, but 4. if there were another gain functtion other than multiple drivers, then it should be capable to be done with 1 or 2. i would venture to say that maybe some of the large tpus had possibly 8 or even 16 sections. needs to be an even number to gave a buck at the ends of every lower ring winding. even thought why not similar windings on the top ring, but that would ruin the mag field affect on the square core windings. ive put a lot of thought into this the last few days. im thinking this is it. and it is much simpler and more easy to understand than the many configurations i have encountered over the years.
for now, ill let that sink in a bit...
mags