Correct. Fair personal use allows you to make a direct lift of someone else's work. We've all seen ideas in quilt shows of magazines that we've used.
It is the directions that are copyrightable.
In the case of a historical piece like the original Dear Jane quilt, the book was openly attributed to the original source. No royalties or permissions are needed if it's been put out for public display.
For living authors, you should reference the authors and preferably ask for permission. You can't copy their directions or pictures and claim them as your own but you can copy their finished product and make it your own by changing sizes or construction methods or in other ways.
But you can't copyright a log cabin block. It's free and open use. You can copyright your version of a log cabin or at least the directions. For example, I've made plenty of log cabins as donation or other quilts that were simply log cabins. One, however, was based on the Colorado Star by Judy Martin. My colors and border treatment were different but I still listed it as "inspired by" when I entered it into a show.
On the other hand, I saw a quilt at a show this Spring that was made from a kit. The maker acknowledged the kit, I was making the exact same pattern but in a different setting and colorways and never saw the kit before in my life because great minds think alike
I'm still considering my project an original and would never reference that because I never saw it before designing my project.