I'm just throwing a question out there that's been bugging me since i did a production of The Wizard of Oz. We scrapped this idea before trying it, but I've been wondering if anybody's had luck with it. During the tornado scene, dorothy sees the images of people and objects through her window in the swirling clouds. If you filmed an actor flying on a broom in front of a green screen, then edited everything but the actor out, could you project the image onto fog through the window? Assuming the window is covered in glass/plastic, and the fog contained to ensure high density, would you be able to see the image in the fog?