The design of digital work systems requires stakeholder involvement in generating relevant work knowledge. It starts with articulation, and proceeds with sharing and aligning this knowledge in more or less structured design spaces. Once the ultimate goal is to develop executable processes in evolving systems, such as cyber-physical environments, specifications require stakeholders to become skilled in programming (concepts) for automated model execution. In this chapter, we demonstrate that models can be created on an abstract, implementation-independent level, while still being executable. The so-called ground models serve as boundary objects for iterative prototyping and interactive validation of specific process scenarios or situations. Remaining on this level of description allows tracing diagrammatic models while running their code, thus reducing system complexity to manageable components and architectures.