[ThinkingPlus]

Visualize a club head on the ground with a pencil attached and perpedicular to the club face. The angle the pencil makes with the ground is essentially the loft of the club. The leading edge of the club face would also be arranged such that it is perpendicular to the target line.

Now, pure rotation of the club head such that the leading edge is no longer perpendicular to the target line about the vertical (anti-gravity) axis would be pure opening / closing of the club face.

Rotation of the club face about the axis comprised of the leading edge of the club face would be pure layback (think pencil coincident with the vertical axis - pointing straight up). Layback is the adding of loft without any change in the open / closeness of the club face. Hope this helps.