One could also say 7+7+7+7 Steps of music.
Don’t forget the duration of the notes/sound/rests. Therefore, duration equals D28 (plus other variables ). This is a musical composition, different logic, different abstractions to other mathematical statements.
The artwork explains some of the starting point (singular) of the structures of a musical composition. Scales, retrogrades and reflections. However, this is but one of a model for creating a musical composition, and that there are an infinitive number of symphonies to be had.