Patterns of [[light]] projected onto a surface by light rays reflected off or refracted through another object. These can be seen on underwater surfaces, when light passes through materials like [[water]], glass, and the like. The bright ripples you can see on the bottom of a [[pool]] or on things close to it on a sunny day are this.

h4. See also

* [[Refraction]]
* [[Ripples]]
* [[Tag group:Image composition]]

h4. External links

* "Wikipedia: Caustic (optics)":http://en.wikipedia.org/wiki/Caustic_%28optics%29
コースティクス 焦散