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 name, Abode of Fancy, implies a structure created to meet some individual artistic requirement. The tea room is made for the tea master, not the tea master for the tea room. It is not intended for posterity and is therefore ephemeral. The idea that everyone should have a house of his own is based on an ancient custom of & the Japanese race, Shinto superstition ordaining that every dwelling should be evacuated on the death of its chief occupant. Perhaps there may have been some unrealized sanitary reason for this practice. Another early custom was that a newly built house should be provided for each couple that married. It is on account of such customs that we find the Imperial capitals so frequently removed from one site to another in ancient days.