Making the air make notes.
I’m fascinated by the relationship between mathematical ratios and what people perceive to be beautiful or pleasing. In music, simple ratios played as intervals like 2:1, 3:2, and 4:3 (an octave, fifth, and fourth, respectively) are generally considered to be pleasing (or boring, depending on your ear). Ratios that contain higher integers, like 5:4 (major third) and 9:5 (minor seventh) are consider more dissonant, complex, or “challenging,” depending on your personal taste and cultural background.