Kyma is an object-oriented environment for music composition written in Smalltalk-80, which, in conjunction with a microprogrammable digital signal processor called the Platypus, provides the composer with a means for creating and manipulating Sound objects graphically with real-time sonic feedback via software synthesis. Kyma draws no distinctions between the materials and the structure of a composition; both are Sound objects. When a Sound object receives a message to play, it transforms itself into a microSound object, i.e. an object representation of itself in the microcode of the Platypus. Thus an object paradigm is used not only in the representation of Sound objects in Smalltalk-80 but also in the microcode representation of those Sound objects on the Platypus.