The layer of music can't be 2. What do you mean?
there cannot be two identical notes in the hierarchy of music. In music, different notes represent different pitches, rhythms and timbres. These elements * * * are isomorphic to form the hierarchical structure of music. If two notes are exactly the same, they will be redundant in music, which will affect the fluency and expressiveness of music. Therefore, the layer of music cannot be 2, which means that there cannot be two identical notes in the hierarchical structure of music.