Stop-Work Relativity
It is useful to show the behaviour of stop-work from different perspectives:
This diagram shows the barrel B with the arbor wheel A and barrel wheel C.
Imagine that the watch is gigantic with people living at B, A and C. The view above is that of "God the watchmaker" looking at this watch universe from outside it. This particular universe is based on a Breguet stop-work design. In his watches the barrel arbor rotates anti-clockwise to wind the mainspring and the barrel rotates anti-clockwise to run the watch; this is the reverse of ordinary watches.
As the watch is wound and as it runs God sees B, A and C rotating. As the watch is wound A rotates anti-clockwise, C rotates clockwise intermittently on its axis and the barrel B does not move. As the watch runs the barrel B rotates anti-clockwise, C (rotating with B) pirrouettes around the barrel arbor and intermittently rotates anti-clockwise on its axis, and A remains stationary.
But what do the people at B, A and C see?
Relative to the person standing on the barrel B, the barrel is the center of the universe and it does not move, while A and C rotate around that person. This is the same as in our universe; relative to you the Earth does not move and the sun, stars and planets rotate around you.
Similarly, relative to the people standing on B and C those wheels are the center of the universe and do not move, and the other wheel and the barrel rotate around the person.
The following animations illustrate these six different perspectives. They are are based on Breguet's 2-pin design, so note that the rotation is the reverse of normal winding and unwinding! Compare them with the Geneva and Maltese Cross stop-work animations.