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?
In 1969, the people in charge of Apollo 11 trusted a 23-year-old engineer in a back room of mission control to make one of the most consequential decisions of this decade-defining mission. And they did so in seconds, without deliberating or debating.
Next time you’re faced with a decision, ask yourself: how can this decision be made on the lowest level? Have you given your team the authority to decide? If you haven’t, why not? If they’re not able to make good decisions, you’ve missed an opportunity to be a leader. Empower, enable, and entrust them. Take it from NASA: the ability to delegate quickly and decisively was the key to landing men on the moon.