The bass clef and the flat, natural, and sharp accidentals derived directly from Gregorian notation. Nowadays "ficta" is used loosely to describe any such un-notated accidentals. The note-naming convention specifies a letter, any accidentals, and an octave number. Assuming enharmonicity, many accidentals will create equivalences between pitches that are written differently. The theme is somewhat chromatic, with frequent accidentals. Difficult key signatures and numerous accidentals were thus largely avoided. The following figure gives the comma values of Turkish accidentals. Schlick rejected keyboards with split accidentals. Their music symbols mainly consist of accidentals and dynamics. A natural minor scale can also be constructed by altering a major scale with accidentals. Effects of key signature and local accidentals do not accumulate. The pitch of the oval musical noteheads can be modified by accidentals. No. 62 has no accidentals (A minor). Accidentals, or chromatics are achieved using fingering techniques. Letter names are modified by the accidentals.