A collective right to the city A collective right to the city was seminally articulated by the French philosopher Henri Lefebvre, a right understood not simply as individual access to the goods, services, and spaces of the city but as the right to change the city in accordance with our deepest desires, to steer the very process of urbanization and the way in which the city nurtures the kinds of people we wish to become. Michael Sorkin, 20 Minutes in Manhattan The Help-Yourself City rights
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. Wikipedia en.wikipedia.org Architectural CausticsCaustic Engineering caustics