Experimental music is a general label for any music that pushes existing boundaries and genre definitions . Experimental compositional practice is defined broadly by exploratory sensibilites radically opposed to, and questioning of, institutionalized compositional, performing, and aesthetic conventions in music . Elements of experimental music include indeterminate music, in which the composer introduces the elements of chance or unpredictability with regard to either the composition or its performance. Artists may also approach a hybrid of disparate styles or incoprorate unorthodox and unique elements .

The practice became prominent in the mid-20th century, particularly in Europe and North America. John Cage was one of the earliest composers to use the term and one of experimental music's primary innovators, utilizing indeterminacy techniques and seeking unknown outcomes. In France, as early as 1953, Pierre Schaeffer had begun using the term """" to describe compositional activities that incorporated tape music, musique concrete, and elektronische Musik. Also, in America, a quite distinct sense of the term was used in the late 1950s to describe computer-controlled composition associated with composers such as Lejaren Hiller. Harry Partch as well as Ivor Darreg worked with other tuning scales based on the physical laws for harmonic music. For this music they both developed a group of experimental musical instruments. Musique concrete (French; literally, "concrete music"), is a form of electroacoustic music that utilises acousmatic sound as a compositional resource. Free improvisation or free music is improvised music without any rules beyond the taste or inclination of the musician(s) involved; in many cases the musicians make an active effort to avoid "cliches", i.e., overt references to recognizable musical conventions or genres.

Now, provide a numbered list of answers to these questions:

1. What is the topic of this article?
2. When did this become prominent ?
3. On what continents was it generally found?
4. Who was one of the first people to use the term?
5. What "instrument" did Lejaren Hiller use in his works?
6. Did Harry Partch and Ivor Darreg use traditional instruments?
7. How did they get these instruments?
8. Is the element of change important to some types of this music?
9. Could this music include nontraditional musical scales?
10. Do some types of this music include multiple styles at the same time?
1. Experimental music
2. mid-20th century
3. Europe and North America
4. John Cage
5. computer
6. No
7. they both developed them
8. Yes
9. Yes
10. Yes