My sketch is a 2D representation. One must imagine that an elbow is a 3D figure. The normal vector i mentioned if a line originated at the elbow's circular face ("hollow") that is perpendicular to this face. Please see the image...
Hello guys and I'm really sorry for my late response, notifications were sent directly to the spam folder... it's been solved.
I made a sketch in order to clarify using only two elbows. I wanna prove that if I use three elbows instead I can not only reach any point in space, but also any normal...
Consider 3 elbows. One extremity is connected to a plane surface and may rotate 360° freely. The available extremity may be connected to another elbow only if the both faces "face" each other (normal vector aligned). Once one connect a second elbow, a second liberty degree is added, since one...