How many sizes each interval comes in
Drawn above with its standard settings, which is almost never how an essay draws it: an essay states the numbers it is arguing about, so the figure a reader meets there is about that argument rather than about the drawing in general. Every option a placement passes is checked against the ones this function actually reads, because an option it does not read is silently ignored and the figure quietly draws what is above instead.
It makes a noise. 9 of its 9 placements carry sound, built from the same numbers as the drawing, offering these buttons: The two sizes of third, in turn, a seven-note set that is not a mode of it, up, seven consecutive semitones, up, the diatonic scale, up, the diatonic set, up, the harmonic minor, up, the pentatonic, up, the whole-tone scale, up.
Called by 4 essays
the blast radius of changing it
Two sizes of every step, which is why the names work
A third is three semitones or four, and every musician learns to call both of them thirds without being told why that is allowed. It is allowed because of a property the diatonic scale has and 448 of the other 461 seven-note selections from the twelve do not.
The same algorithm made a Cuban rhythm
Ask Bjorklund's algorithm for seven onsets in twelve steps and it returns 101101011010, which read as pitch classes is the natural minor scale. That function has been producing the tresillo and the cinquillo here from the beginning, and nobody has said that the scale field's central object comes out of it unchanged.
Why seven
Four properties, each shared with some other set. Run all four over every subset of the twelve, at every size from two notes to eleven — three hundred and forty-nine shapes in all — and exactly one has all four at once. It is the diatonic set, and it is the only survivor in the whole twelve-note universe.
The only sizes a fifth will make
Stack pure fifths and fold them into an octave, and at almost every number of notes the result has three or more different step sizes. At 2, 3, 5, 7, 12, 17 and 29 it has exactly two — and at no other size below thirty. The pentatonic and the diatonic set are not two discoveries. They are neighbours in one series, and it is the comma's series.