Rooms designed for presentations often don’t have windows so that they can be easily darkened for projectors to work better. Where I grew up, it was quite comm

Rooms designed for presentations often don’t have windows so that they can be easily darkened for projectors to work better. Where I grew up, it was quite common for classrooms to have an overhead projector [1] equipped with a long scroll of transparent film. The instructor would give their lecture sitting at the projector and writing on the film instead of at a blackboard. [1] https://simple.wikipedia.org/wiki/Overhead_projector#/media/File:OHP-sch.JPG https://simple.wikipedia.org/wiki/Overhead_projector#/media/...