Is it not fascinating that this writer has embodied his entire being into his musical soul?
His signature portrays the importance, not only to himself but also to his public persona, of his musicality. He does not need a first name or a surname - a musical symbol represents who he is in his entirety!
A signature is your personal representation of yourself and can describe your profession such as in this example.
When a writer uses symbols in his signature it can either be done on purpose or it can be done unconsciously. It would greatly depend on the level of self-knowledge in the particular individual.