~ ~ This chapter detailed the choice of a domain for the Concurrent Engineering Demonstration System which would meet the requirements of being intuitive and yet complex enough to offer several aspects from which to critique a design. The details of the components, both concrete and abstract were discussed, as were the actions involved in designing a tower within the domain. Finally, the various aspects which enable the system's multi-disciplinary view were introduced. This domain had to be decided before SNEAKERS could even be designed. The knowledge presented in this chapter was used in designing the overall system. The next chapter presents the software design of SNEAKERS, from which the implementation was drawn.