Sand on a vibrating plate gathers along its still lines. Here an idealised standing-wave field reveals those lines directly, with nearby contours forming a delicate echo.
Ernst Chladni, 1787 · idealised standing-wave figures
The drawing uses a cosine-mode approximation on a square, not a full elastic-plate simulation. With blend at zero, the central contour is the nodal set. Echo lines follow nearby field values; blending a second mode is an artistic extension rather than a single physical resonance.
wavegrid