Musical symbols are marks and symbols in musical notation that indicate various aspects of how a piece of music is to be performed. There are symbols to communicate information about many musical elements, including pitch, duration, dynamics, or articulation of musical notes; tempo, metre, form (e.g., whether sections are repeated), and details about specific playing techniques (e.g., which fingers, keys, or pedals are to be used, whether a string instrument should be bowed or plucked, or whether the bow of a string instrument should move up or down). Lines Clefs A clef assigns one particular pitch to one particular line of the staff on which it is placed. This also effectively defines the pitch range or tessitura of the music on that staff. A clef is usually the leftmost symbol on a staff, although a different clef may appear elsewhere to indicate a change in register. Historically, clefs could be placed on any line on a staff (or even on a space), but modern notation almost exclusively uses treble, bass, alto, and tenor clef. Rhythmic values of notes and rests In American usage, musical note and rest values have names that indicate their length relative to a whole note. A half note is half the length of a whole note, a quarter note is one quarter the length, etc. Breaks Accidentals and key signatures Common accidentals Accidentals modify the pitch of the notes that follow them on the same staff position within a measure, unless cancelled by an additional accidental. Key signatures Key signatures indicate which notes are to be played as sharps or flats in the music that follows, showing up to seven sharps or flats. Notes that are shown as sharp or flat in a key signature will be played that way in every octave—e.g., a key signature with a B indicates that every B is played as a B. A key signature indicates the prevailing key of the music and eliminates the need to use accidentals for the notes that are always flat or sharp in that key. A key signature with no flats or sharps generally indicates the key of C major or A minor, but can also indicate that pitches will be notated with accidentals as required. The key signature examples shown here are as they would appear in treble clef. Flat key signatures Sharp key signatures Microtones There is no universally accepted notation for