A loooooooong time ago ... back when I had an iPhone, because (ironically) I couldn't afford anything cheaper at the time ... I found an app that played birdsong and you could evolve the sound between birds by moving the locus (a dot on the screen) through the space between different species.

Then, iirc, when you found something you liked, you could save it and use it as a new starting point ... further evolving it by the same process.

I forget what it was called now ... and it's probably long since gone from the app store (far too niche) ... but, if I can find that phone, (and it still powers on), then, if you'd be interested, I'll find out what it was for you.