You have not identified the tropes correctly. The first one is not metaphor. You need to replace one sign with another, and this is a hybrid sign. Allegory is typically addressing a bigger cultural, social, political statement than music. Plus a circle is not a "concrete device", it's an abstract geometric shape. Ian, if you'd like to try this exercise again I will accept it for re-evaluation. It is important that you can successfully identify tropes in other design work. Just notify me when you have posted.