The bright point in the middle of a shadow that Poisson derived to disprove wave optics and Arago went and found — with Fresnel zones giving the ring spacing rather than painted circles.
Drawn with: a WebGL2 shader.
Reacts to and looks like: gpu, webgl2 and audio-reactive.
Family: Visualiser.
Runs in your browser. The preview above is the same program the renderer uses.