caustics
Caustic (optics)
Caustics made by the surface of water.
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.
Hiding Images in Plain Sight
An Article by Matt FerraroI recently made a physical object that defies all intuition. It's a square of acrylic, smooth on both sides, totally transparent. A tiny window.
But it has the magic property that if you shine a flashlight on it, it forms an image.
Caustic Engineering
An Article by Geoff ManaughA 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.
Architectural Caustics
A Research PaperTo 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?
Time and space
Tones appear placed and directed predominantly in time from before to now to later.
Their juxtaposition in a musical composition is perceived
within a prescribed sequence only.
Horizontally, the tones follow each other,
perhaps not in a straight line, but of necessity in a prescribed order
and only in 1 direction – forward.
Tones heard earlier fade, and those farther back disappear, vanish.
We do not hear them backward.Colors appear connected predominantly in space. Therefore,
as constellations they can be seen in any direction and
at any speed. And as they remain, we can return to them repeatedly
and in many ways.
This remaining and not remaining, or vanishing and not vanishing,
shows only 1 essential difference between the fields of tone
and color.The accuracy of perception in one field is matched
by the durability of retention in the other, demonstrating
a curious reversal in visual and auditory memory.