Music notation or musical notation is any system used to visually represent aurally perceived music played with instruments or sung by the human voice through the use of written, printed, or otherwise-produced symbols, including ancient symbols or modern musical symbols and including ancient symbols cut into stone, made in clay tablets or made using a pen on papyrus, parchment or manuscript paper; printed using a printing press (ca. 1400)s, a computer printer (ca. 1980s) or other printing or modern copying technology. Types and methods of notation have varied between cultures and throughout history, and much information about ancient music notation is fragmentary. Even in the same time period, such as in the 2010s, different styles of music and different cultures use different music notation methods; for example, for professional classical music performers, sheet music using staves and note heads is the most common way of notating music, but for professional country music session musicians, the Nashville Number System is the main method.