Once upon a time I was reading a Popular Mechanics article, the title of which eludes me. Something about playing different music for different parts of a dance floor. They were describing a way to focus sound towards different people.
What struck me about the idea was that there was a way to focus sound. It was a piece of mesh of some sort, which acted as a lens for ultrasonics. This sparked an idea for what ended up being the most complex and expensive of my hobby projects to date.
Imagine using such lenses to focus sound onto a plane of microphones. Just like light in a camera. One microphone is one pixel. An ability to see sound.
I didn’t actually read Daredevil comics until much later, but those who have can see where this is going.