You are writing a play.
Only, there is no stage and there are no lines. Your “cast” consists of the instruments of the ensemble.
Each character in your play is represented by a distinctive theme or motive.
Imagine how you might advance the plot–the ebb and flow of drama–through the interaction between the characters (i.e., your themes/motives) and their particular developmental paths.
The challenge: could you craft this piece in such a way that it would be satisfying even to a listener unaware of the theatrical scaffolding?