Mirror plane — where it appears
Named by 2 essays across 2 fields — each of them below, with the objects they name alongside it.
A mirror is a second camera
Reflect the scene and photograph it, or reflect the camera and photograph the scene. The two routes disagree by 315 px and agree to the last bit once one axis of the image is reversed — which is the whole of why a mirror is said to swap left and right, written down.
Three constructions, one map
A shadow cast on a floor, an anamorph painted on one, and a reflection in a mirror were built in three different fields of this site, three phases apart, each with its own derivation and its own figure. Decomposed into their fixed points and lines, three of them are the same kind of map — a central collineation with a line of fixed points — and the fourth, a rectification, is not. That difference separates changing where a picture is seen from, from changing one picture into another.
Named alongside it
The objects these essays reach for when they reach for this one.
ReflectionAnamorphosisCentral collineationCharacteristic ratioChiralityCollineationDemonstrationDesarguesElationFixed pointHandednessHomography