Two tones in the ratio 3 to 2
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. 7 of its 7 placements carry sound, built from the same numbers as the drawing, offering these buttons: One at a time, Play 2:1, Play 3:2, Play 45:32, Play 5:4.
Called by 2 essays
the blast radius of changing it
Two notes and a ratio, which is the whole of consonance
Sound two tones together and the pair either settles or does not. What decides it is the ratio of their frequencies, and the rule is that simpler ratios settle — which is two and a half thousand years old and still not quite an explanation.
Somebody has to pay the comma
A choir has no frets and no keys, so it can tune every chord exactly — and a common progression sung that way arrives a comma flat, every circuit. The freedom a keyboard lacks turns out to be a freedom about where the error goes rather than whether there is one, and the two costs always add to the same number.