I am helping the Very Special Arts program, and we are producing a play with the front of a farmhouse for the main set. In the play, the main character goes off into a dream, and the director wants to project a slideshow of pictures behind her. An idea she had was to paint a scrim with the top of the house, and only build the bottom. When the dream comes, she will then have a rear projection screen show the slideshow behind the scrim. Do you have any ideas that would be fairly easy, but still fairly inexpensive.