With a fresh Jenga tower, you can take a block from the top and place it on top of its previous neighbors. The overall shape of the tower is off, and on a small level, the balance of the tower shifts. If you keep removing and restacking blocks at the top, you can throw the balance of the tower off and send the whole thing crashing to the table.
You can also take pieces from the middle. But you know that the integrity of the Jenga tower will be very clearly affected. Not only do you have to be careful about how you dislodge and move pieces, but you must gingerly set them on top of the tower so as not to tip the whole structure over. Put a piece on the wrong side, and the whole tower’s liable to tip. Pull too many from the middle on the same side, and your tower’s going down.
If you are feeling bold, you can also try to pull a few blocks from the bottom three rows of blocks, and this is where your understanding of the importance of human posture really solidifies. If you pull just one block off the bottom row, the entire structure becomes extremely unstable. If you pull another block from the next row up, your tower will be in pieces (unless you’re an extraordinarily good Jenga player).
The structural integrity of the Jenga tower depends upon all the blocks being balanced and aligned. What happens at the bottom affects the balance of what’s above. What happens in the middle affects the balance of what’s below AND above. What happens at the top affects what happens below. If any area of the tower becomes too unbalanced, the entire tower collapses.
Your body is one big Jenga tower layered over with a complex network of blood, muscles, and nerves. The blood, muscles, and nerves don’t change the fundamental fact that what happens in any one part of the tower affects the balance of the whole.