This document has been revised, and hopefully improved.
The terminology came from Dr. Gaddy, and the contributions of Steve Culver are most appreciated, even if he doesn't like 'scrolls' wink
https://docs.google.com/document/d/1zMmG-80ZUWwiLDbjBNk-wiOdDxKrhQL6jMNs5L2XVfc/edit

I've added several images that should help. An "American Flag" barrel clearly showing 2 wavy 'zipper' rod to rod welds between 2 straight ribband edge welds (down the middle of a smaller scroll) = 3 Iron

[Linked Image from photos.smugmug.com]