 A camera obscura device consists of a box, tent, or room with a small hole in one side.Light from an external scene passes through the hole and strikes a surface inside, where the scene is reproduced, inverted, (thus upside-down) and reversed (left to right), but with color and perspective preserved.In order to produce a reasonably clear projected image, the aperture has to be about 1/100th the distance to the screen, or less.