"Circular Dies are fun and relaxing" and watermarks and knifes and envelope size & color.
"Nape of neck" "Back of head" "Back of neck"
If (as said) an artifact from old illustrations of the paint program used to generate the lines, maybe time for new illustrations with consistent definitions.
I'm a big fan of the catalogs and guide, and can usually figure out the dies, so this is just a small rant
And this is only one part of ID'ing the correct UPSS number.
Looking at a lot of them it gets easier, and side by side comparison helps.
Images from catalog.
First two say nape of neck, almost all others say back of head
Only image that shows (how to) measure head for all values. Without explanation, seems a bit overexaggerated.
From Scott Specialized: "back of neck". Scott seems to point in the illustration from the general direction of the nostrils to where the curve of the head first meets the neck (not shallowest part). And you can see from this illustration you could miss judge with part of the nose tip covered in ink.