More on Delivery Paths
As it has already been stated, it is still a straight line effort even for the Circle Path.
A Straight Line Delivery Path means it's more straight than the Circle Delivery Path. It's not a long dead straight line like you see in those photos in the book. Homer was doing this to make his point loud and clear.
For those who want to explore more, try this:
Make a normal golf swing with your driver.
Specifically in this case, normal means:
shoulder width stance
slight knee bend at address
straight line effort of thrust on downstroke
axis tilt on downstroke
reasonably stable head.
Now try to make your usual swing but set up as follows:
feet together
knees straight
straight line effort of thrust on downstroke
You will be executing a Straight Line Delivery Path in the first example, and a Circle Delivery Path in the second, even though it's a straight line effort for both. Why? Because your lack of knee flex and narrow stance has prevented you from sliding your hips which means you can't tilt your axis. Which means no Straight Line Delivery Path.
Remember, the model in 1-L doens't need to Axis Tilt, so it's "Delivery Path" is always going to be the same.