Sometimes when the interval between the lowest note and the highest note stays the same the chord seems to have the same height, but it really doesn’t if the intervals between the adjacent notes within the chord are changing. (...)
From the Continuation section:
* My 360 Chords for orchestra used all the seven-note chords where the intervals between adjacent notes were 3, 4, 5, 7, 8, and 9 semitones. With six adjacent intervals I could have formed 6! = 720 possible chords rather than 360, but I eliminated the ones with the small intervals in the bass, because the sound was too muddy. See the first bar of 360 Chords in the illustration page of this chapter. What was the range of the full chord?