In this article, the author emphasizes the importance of "working" walls in children's programs. Children's programs need "working" walls (and ceilings and floors) which can be put to use for communication, display, storage, and activity space. The furnishings also work, or don't work, for the program in another sense: in aggregate, they serve as sight and sound conditioners. When effective, they modulate and direct sensory stimulation in service of program goals. The author presents tips on how to make "working" walls wonderful.