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Cymatics. It's sound interference drawing some peculiarly complex, but cool looking patterns. Edit: I've tried to find actual math behind those pictures and only found piles of pseudoscience. There's a CymaScope app that draws them, but they are super secretive about it. I suspect that it's just the interference pattern in a tibetian bowl or a cup of tea. It's almost suspicious that wikipedia has detailed scientific articles with hardcore math on dumb topics, but not only wikipedia, but the entire math community seems to carefully avoid this topic. Edit2: I think the math behind this is https://en.wikipedia.org/wiki/Normal_mode. In this case, the picture can likely be derived by numerically solving the diff equation of a sound wave with a boundary condition on a circle. Edit3: This lead me to https://en.wikipedia.org/wiki/Vibrations_of_a_circular_membr... with Bessel equations and all the good stuff. Solving it (numerically) would supposedly create the cool picture of the 432 Hz note. Edit4: And I've returned to where I began: cymatics, cymaglyphs and that cymascope. It gives an impression of a lazy pseudoscience at first, because of the somewhat sloppy language they use, but after watching a John Stuart Reid's presentation (watch it, it's only 40 mins), I had to change my opinion. The indeed capture the interference patterns created by sound in a bowl of water and a picture of that rapidly moving pattern is called a "cymaglyphs". I'd say, visualizing sound and music is a solved problem and the solution is called cymaglyphs. Obviously, an app can't use a bowl of water to solve the diff equations, but it can do that numerically with a decent precision, and apply some smoothing techniques to deal with the rapid evolution of these cymaglyphs.