Cage, Morton Feldman and Witold Lutosławski. A more commonly known example of chance-based, or indeterminate, music is the sound of wind chimes jingling in a breeze. The 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 the creation of popular music and traditional music songs and instrumental pieces, and to include spontaneously improvised works like those of free jazz performers and African percussionists such as Ewe drummers. In the 2000s, composition is considered to consist of the manipulation of each aspect of music (harmony, melody, form, rhythm and timbre), according to Jean-Benjamin de : Terminology Since the invention of sound recording, a classical piece or popular song may exist as a recording. If music is composed before being performed, music can be performed from memory (the norm for instrumental soloists in concerto performances and singers in opera shows and art song recitals), by reading written musical notation (the norm in large ensembles, such as orchestras, concert bands and choirs), or through a combination of both methods. For example, the principal cello player in an orchestra may read most of the accompaniment parts in a symphony, where she is playing tutti parts, but then memorize an exposed solo, in order to be able to watch the conductor. Compositions comprise a huge variety of musical elements, which vary widely from between genres and cultures. Popular music genres after about 1960 make extensive use of electric and electronic instruments, such as electric guitar and electric bass. Electric and electronic instruments are used in contemporary classical music compositions and concerts, albeit to a lesser degree than in popular music. Music from the Baroque music era (1600–1750), for example, used only acoustic and mechanical instruments such as strings, brass, woodwinds, timpani and keyboard instruments such as harpsichord and pipe organ. A 2000s-era pop band may use electric guitar played with electronic effects through a guitar amplifier, a digital synthesizer keyboard and electronic drums. Piece Piece is a "general, non-technical term [that began to be] applied mainly to instrumental compositions from the 17th century onwards....other than when they are taken individually 'piece' and its equivalents are rarely used of movements in sonatas or symphonies....composers have used all these terms [in their different languages] frequently in compound forms [e.g. Klavierstück]....In vocal music...the term is most frequently used for operatic