Zoom-in on little loop of rope. A worker is hanging full-body from this loop via their toes. When they move, the loop sways quickly in response to their movement, and then sways slowly as their inertia pendulums when they are still. Sometimes the worker slips a little bit, or adjusts their ankle or toes.
The whole rope and worker hanging are slowly twisting and untwisting vertically, in a different kind of pendulum action. The workers don't usually seem to notice this.
