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?
It is true that [the artist], like everybody else, derives remuneration from his work (though not, strictly speaking, profit in the financial sense, of the word, since what he invests in his work is not money but time and skill, whose returns cannot be calculated in percentages). The remuneration is frequently beyond the amount necessary to enable him to go on working. What is remarkable about him is the way in which he commonly employs the escape-from-work which the extra remuneration allows him. If he is genuinely an artist, you will find him using his escape-from-work in order to do what he calls “my own work”, and nine times out of ten, this means the same work (i.e. the exercise of his art) that he does for money. The peculiar charm of his escape is that he is relieved, not from the work but from the money.
What distinguishes him here from the man who works to live is, I think, his desire to see the fulfilment of the work.