What we needed was the sound of wings fluttering. What we were desperate to avoid was having ornithopters sound like helicopters. Because that's this circular motion and we wanted fluttering motion. And we just loved the kind of buzzing, insect-like buzzing that these vibrating rubber bands gave us with these. So this was a component of the start-up when they first start flapping. And you can hear it's already different if I go slow. But it just makes this deliciously weird buzzing noise. Really satisfying. And it's fun to play with. And then the key to it too is that just like any instrument you can tune the rubber bands. If I change the tension point, the frequencies change. That was higher pitch. Yeah. Different interval. And a little more dissonant.