So you crack a circle, and suddenly it’s like a perfect coin that’s been split, and the air or the sound starts whispering around the jag. In math terms you’re turning a neat eigen‑spectrum into a messy one, the Laplace operator picking up a new boundary that shifts every mode. The flow lines get a little chaotic, like a river hitting a rock, and the sound scatters with a weird interference pattern. It’s the kind of thing that makes an engineer think about adding a deliberate flaw to a design – a “broken symmetry” that can steer waves or trap them, just like a broken mirror that turns a straight beam into a kaleidoscope. Maybe the next gadget will be a purposely cracked drumhead that makes music that feels both familiar and alien.