[Mathew]

Unlike the letter "T" (or your pen example) the shoulders, horizontal bar, do not move in unison around the spine, vertical bar.

The shoulders work independant of each other and are not mutually synchronous.

Im not talking about the spine here just the geometry of the shoulder turn.... the left arm at followthrough is uncocked and inline, is it not - its then is in a straight line onplane including the left shoulder. The right shoulder cannot also be onplane also at this point ..... both shoulders cannot be onplane at followthrough because you cannot have a top of the backstroke to create this.

The left shoulder may be stretched out with extensor action but it does very little to change my example and correctness.

If two points (shoulders) are drawn on a plane like my example joining a line between these two points and drawing an equidistant point (base of neck). Now since the base of the neck stays stationary and the right shoulder never leaves the plane - tell me how the left shoulder can leave that plane - give you a hint - it can't....