Seventh chord an augmented fifth, and an augmented seventh (i.e., a sequence of 3 major thirds, such as C–E–G–B), is a rarely used tertian seventh chord. The reason is that the augmented seventh interval is enharmonically equivalent to one entire octave (in equal temperament, 3 major thirds = 12 semitones = 1 octave) and is hence perfectly consonant with the chord root. The seven commonly used chords are: Seventh chords can also be constructed using augmented or diminished thirds. These chords are not tertian and can be used in non-tertian harmony. There are many (mathematically, 64) chords that can be built, however,
Octave glissando upward with the right hand. The "Alborada del gracioso" from Maurice Ravel's "Miroirs" contains glissandi in thirds and fourths in one hand. Octave glissando An octave glissando is a glissando played on the piano by maintaining a constant distance of an octave between the thumb and finger used to execute it, and shifting the whole hand in the direction of the glissando. Due to the positions of the thumbs on the player's hands, octave glissandos are almost always executed upwards with the left hand and downwards with the right. However, exceptions include Balakirev's "Islamey", where players are instructed to execute