Professor Michio Kaku says in his book Hyperspace (page:329)
"The underlying physical principle behind string theory is unknown"
However, as an architect I found an interesting form solution: "transformable rigid single- or compounding rings" formed by 4x mutual hinged quarter rings, called strings ,which seem to be formed by mutual smaller micro Strings to form Hinges with 90 degree freedom.. Only one particle seems to beneeded for the Universe and even multiverse. (below)and: https://vixra.org/pdf/1903.0347v1.pdf
Now the new Mathematics behind this system including rotation hinges, should be discovered, which seems to be not easy according to professor G.'t Hooft.( Uni-Utrecht)
The Universe of Wheels and Gears
made by "Magnetic Primal Particles" forming rings transformable by hinges.