The idea of modularity should also be continued in the UI. Products should ideally be complementary to each other.
Therefore we aimed for a model of the "Shared UI" for the interface. Individual components function in a self-contained manner and can be used in other contexts. A product thus consists of its own components, specifically created for the use case, and shared components.
Mental spaces formed a guideline for the assignment of concrete user stories and resulting functions. The mental model should serve the correct assignment of new ideas & requirements throughout the entire product life cycle. Therefore, the creation of mental spaces had to have a certain robustness.