So, explain to me again, why these lines are important and not just, ho-hum, lines.
HB
As per Yoda's post, the Angle of Attack (caddy view) describes Impacts Downwards direction. The Angle of Approach describes the Forward and OUTWARD direction to impact from the players perspective. Contrast this on plane, inside out impact (not stroke) to Steering. There is a big difference perceptually. And in terms of the direction of Thrust.... you actually do swing OUT for a square plane line !!! Even when the clubhead does not cross over the plane line!!!