You did the supers and subs correctly as far as I can tell. I have incorporated the latest (and better) suggestion for the "bun" symbol. It is only 3 cells and much easier to read. Follow rule XVI sec. 107 which says: for a shape not in the Basic Shapes list, use the shape indicator and one or more letters representing the name of the shape. As you can tell, we all continue to learn when it comes to the Nemeth Code.