Musical composition is a term that describes the composition of a piece of music. Methods of composition vary widely from one composer to another, however in analysing music all forms — spontaneous, trained, or untrained — are built from elements comprising a musical piece. Music can be composed for repeated performance or it can be improvised: composed on the spot. The music can be performed entirely from memory, from a written system of musical notation, or some combination of both. Study of composition has traditionally been dominated by examination of methods and practice of Western classical music, but the definition of composition is broad enough to include spontaneously improvised works like those of free jazz performers and African drummers such as the Ewe drummers.