Sound arranged in time serves as the medium for music, which is both an artistic and cultural endeavor. Common components of music are pitch, which controls melody and harmony, rhythm, which includes tempo, meter, and articulation, dynamics, which determines loudness and softness, and timbre and texture, which are sometimes referred to as the “color” of a musical sound. Certain elements of music may be emphasized, de-emphasized, or omitted depending on the style. Music is performed using a wide variety of instruments and vocal styles, from singing to rapping. There are compositions that are exclusively instrumental, compositions that are only vocal (like songs without an instrumental accompaniment), and compositions that combine singing and instruments.