Musical note indicated by placing the symbols in the key signature, which then apply implicitly to all occurrences of corresponding notes. Explicitly noted accidentals can be used to override this effect for the remainder of a bar. A special accidental, the natural symbol , is used to indicate an unmodified pitch. Effects of key signature and local accidentals do not accumulate. If the key signature indicates G, a local flat before a G makes it G (not G), though often this type of rare accidental is expressed as a natural, followed by a flat () to make this clear. Likewise (and more
Musical note commonly), a double sharp sign on a key signature with a single sharp indicates only a double sharp, not a triple sharp. Assuming enharmonicity, many accidentals will create equivalences between pitches that are written differently. For instance, raising the note B to B is equal to the note C. Assuming all such equivalences, the complete chromatic scale adds five additional pitch classes to the original seven lettered notes for a total of 12 (the 13th note completing the octave), each separated by a half-step. Notes that belong to the diatonic scale relevant in the context are sometimes called "diatonic notes";