[6bmike]

Your concept is correct, woodandcoal.

If the Clubshaft was a laser beam, then the orbiting (and tracing) Sweetspot would, in fact, simultaneously 'point at' and cover the Plane Line. Consequently, there would be no Arc of Approach (to the Plane Line) and hence no curved 'Visual Equivalent'. Then, the only available reference line for 'On Plane' Clubhead Delivery would be the Straight Plane Line itself.

But...

The Clubshaft is not a laser beam. Its length is finite, and it cannot grow longer during the Backstroke or shorter during the Downstroke. Therefore, the orbiting Sweetspot can only 'point at' the Straight Plane Line as it 'covers' its own true curved Path.

Now the golfer has available two Delivery Lines: the true geometric Plane Line and its Visual Equivalent, the curved Arc of Approach.

woodandcoal and others, you all just leap frogged ahead of the class. This concept of "pointing at the Plane Line" -Tracing and "covering its own true curved Path" - Covering, is a concept that has taken some of us years to 'get.' In fact I knew several highly TGM educated friends that scratched their heads over this for a long time before the bulb lit bright.

And now it looks so easy to understand.