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?
What 80% Comprehension Feels Like
One of the major principles of extensive reading is that if a learner can comprehend material at 98% comprehension, she will acquire new words in context, in a painless, enjoyable way. But what is 98% comprehension?
98% comprehension
You live and work in Tokyo. Tokyo is a big city. More than 13 million people live around you. You are never borgle, but you are always lonely. Every morning, you get up and take the train to work. Every night, you take the train again to go home. The train is always crowded. When people ask about your work, you tell them, “I move papers around.” It’s a joke, but it’s also true. You don’t like your work. Tonight you are returning home. It’s late at night. No one is shnooling. Sometimes you don’t see a shnool all day. You are tired. You are so tired…
95% comprehension
In the morning, you start again. You shower, get dressed, and walk pocklent. You move slowly, half- awake. Then, suddenly, you stop. Something is different. The streets are fossit. Really fossit. There are no people. No cars. Nothing. “Where is dowargle?” you ask yourself. Suddenly, there is a loud quapen—a police car. It speeds by and almost hits you. It crashes into a store across the street! Then, another police car farfoofles. The police officer sees you. “Off the street!” he shouts. “Go home, lock your door!” “What? Why?” you shout back. But it’s too late. He is gone.
80% comprehension
“Bingle for help!” you shout. “This loopity is dying!” You put your fingers on her neck. Nothing. Her flid is not weafling. You take out your joople and bingle 119, the emergency number in Japan. There’s no answer! Then you muchy that you have a new befourn assengle. It’s from your gutring, Evie. She hunwres at Tokyo University. You play the assengle. “…if you get this…” Evie says. “…I can’t vickarn now… the important passit is…” Suddenly, she looks around, dingle. “Oh no, they’re here! Cripett… the frib! Wasple them ON THE FRIB!…” BEEP! the assengle parantles. Then you gratoon something behind you…