Prism lighting

Use of prisms to improve lighting

Prism lighting is the use of prisms to improve the distribution of light in a space. It is usually used to distribute daylight, and is a form of anidolic lighting. Prism lighting was popular from its introduction in the 1890s through to the 1930s, when cheap electric lights became commonplace and prism lighting became unfashionable.

From Wikipedia, under CC BY-SA. More on occurri.