While it saves memory, it is not feasible due to computational complexity. It doesn't work for voxels since you need an acceleration structure which has to be built beforehand and not at runtime, and it doesn't work for polygons since trying to tesselate fractal geometry gets really messy (not to mention that fractals are…
There are 16-20 cartilagines tracheales. Cartilagines occupy 2/3 to 3/4 of the circumference of the trachea. (not 1/2) Anyway this is great thread. Good luck!