Box

Made of 6 "pieces", put together in a way to create a 'containment'
Now not one of those pieces on it's own could hold anything. It is the construction together, and some attachment to hold the whole thing into place - that's the key.
ie. the complete system makes it work

1. Just like the human body. A series of little systems that if synergistically 'molded' work brilliantly.

2. The musculoskeletal with the Neuromuscular with the endocrine with the nervous etc...

3. Simple yet complex!

4. Let's focus on the simple - about how the human moves.
a.) The core is :- a straight rod (the spinal column) with 2 sets of ball & socket areas.
b.) So the key necessity is keeping the 'straight rod' stable, and letting the ball & socket areas rotate.

5. Sounds simple
a.) amazing how much fitness 'expertise' out there forgets the simple basis of human function.

Juice-Up with Rotation Fitness