Nature creates round objects all the time (stones in a river, a hedgehog in a ball,…), but the principle of an axle is not found as far as I know.
Nature creates round objects all the time (stones in a river, a hedgehog in a ball,…), but the principle of an axle is not found as far as I know.
If your knee can turn 360°, you should talk to some scientists, so that they can study you.
Rotating is in nature, but as you said: always with a maximum rotation, never free without limits.