Chladni’s Law F=C(m+2n)^p
The Chladni Plate, named for its inventor Earnst Chladni, allows us to see the behavior of sound waves.
Instruments made of wood, string, and metal move in complex and nonlinear ways; that's partly why the sounds they make are so rich.
We can see this by scattering sand on a plate, and vibrating the plate at different frequencies.
Each frequency sets up a different pattern of oscillations: the sand is tossed off the areas that are vibrating up and down, and it gathers at the still points between them. In the same way, the soundboard of a violin, or the bell of a trumpet, responds differently to each frequency, making every note unique.