Single strings seem to be 2 Fermions (e+ and e-) and all Photons.
All other fermions (Quarks) are combined out of one or more e+ or e-, compounded with one or more photons.
The building blocks of the strings should have a much smaller dimension, able to support the transformation af the strings by three hinges at three intersections of the particles.
As a result, it seems a logical conclusion that all propeller shaped Fermions are forming so called Calabi Yau surfaces while rotating inside the oscillating Axion string lattice (or tubes) made of closed strings.
see also: Ball Lightnings and local Herbig Haro systems, are micro black hole string knots. below.
The smalles Black Hole is a mass less Ball Lightning producing a plasma tail as propellant.