Once a century, a very special day comes along. That day is today — 9/16/25. Pi Day (3/14) often comes with sweet treats; Square Root Day (4/4/16 or 5/5/25, for example) has a certain numerical rhyme.

In this scale, the ratios between successive steps are either the whole tone 9/8 (204 cents) or the diatonic semitone 256/243 (90 cents). However, the corresponding disadvantage is that no matter how ...