In optics, a caustic is the envelope of light rays reflected or refracted by a curved surface or object, or the projection of that envelope of rays on another surface. The caustic is a curve or surface to which each of the light rays is tangent, defining a boundary of an envelope of rays as a curve of concentrated light.
A piece of milled plexiglass acting as a projecting lens; via the Computer Graphics and Geometry Lab at the École Polytechnique Fédérale de Lausanne
New milling techniques applied to glass and plexiglass panels could be used to “create windows that are also cryptic projectors, summoning ghostly images from sunlight.”
[Pauly and Bompas] hope that the technique will be used in architectural design, to create windows that mould sunlight and throw images or patterns onto walls or floors,” which, if timed, milled, and manipulated just right, could produce a slowly animated sequence of images being projected by an otherwise empty window during different times of day.
To control the shape of a caustic pattern generated by a specular or refractive surface, we need to solve the inverse problem: how can we change the surface geometry, such that incident light is redirected to produce a desired caustic image?
The best way to experience a restaurant, I have always felt, is by eating exactly what it wants to feed you. I do not want choices. I want the best thing. A restaurant might have five or ten best things, but it cannot have 45. There are many infuriating things about the world, but one of the more fixable is the sensation of acute regret from having ordered wrong. Why are there possibly wrong orders? Recently, I was at a fancy restaurant with great pastas and bad pizzas. So cut the pizzas!
A kitchen that focuses on its strengths turns out consistently excellent things, even if that results in fewer total things.