Making music with players always seems odd to me. Its often this parallel between giving them full control to make whatever they want or doing it in a way that is more the developer telling them to press x button to make sick tunes. With that said I really like the idea of mixing between different musical motifs to encourage a psuedo creation of new music for the player while not let them self discourage with the complexity that can go into a piece of music. I do think there could be more clear interaction or representation between the blobs and the sounds being created. Say for instance if you're introducing a buzzy sound the blobs start having jagged edges or a square wave that makes the motion more linear or something. Overall super cool toy you have on your hands here.