The execution behavior of a system or a product can often be specified by a set of operations (sometimes called tasks, actions or activities). The process to specify these operations seems to be a real challenge in various situations, for example when designing automation systems or keeping track of the work at an emergency department. To be flexible during design and development, is about coping with uncertainty. However, in practice, specifying operation behavior is often quite inflexible because every possible execution route is explicitly defined. This approach is sometimes refereed to as point-based engineering, which is characterized by the early selection and approval of a single “best” specific solution. This approach can result in neither a robust nor a flexible design process with many rework iterations. This paper instead suggests a set-based operation specification approach that does not explicitly defines operation routes, where instead the operation behavior is specified using the execution restrictions in transition conditions for each operation. This enables the possibility to create multiple projections of the operation relations to enable better understanding. This is accomplished by creating various Sequences of Operations, sequences of operations (SOP), including a multiplicity of sequences and operation relations. Two example case studies are presented, where the first show the development of an automation system and the second study uses sequence projections in an emergency department at a hospital to handle the complex and flexible operation (task) behavior.