These symbols are fussier than necessary, because they are trying to be cute about both the mapping to the alphabetic scale and slavishly sticking with circles.

What is required is a sequence of length seven (for convenience) that allows sharp/flat prefixes and time length suffixes. Circles are merely one option.

If written by hand, there will be ambiguities between C, Dot, Empty, and Full. I think a graphic design artist had too much fun with this project...