As the name implies, collaborative design is a process performed by many designers. Each designer makes a subset of the decisions comprising a design and must modify his or her decisions when they adversely influence some aspect of the design. To complicate the task, each designer is equipped with his or her specific schema or world-view that makes communication between them difficult. Definitions of commonly used objects can serve as examples of this difficulty. Movable partitions may be seen as "walls" by space planners but would not fit into that category from the viewpoint of structural designers. Others may think of the word "wall" as associated with amounts and color of paint while a computer graphics specialist may be more concemed with the "two sidedness" of the "wall" object for manipulation purposes. The attribute of two sides has external and imemal implications when related to fire codes, insulation, or covering.