Today?s complex computational and embedded systems compute complex quantities from complex inputs, with behavior dependent upon the (distributed) state of the system and its environment. Describing the intended behavior of such a system is challenging. The most natural and commonly used approach is to give a collection of scenarios, where each scenario is a sequence of inputs and expected outputs. An analyst elicits scenarios from subject matter experts (SMEs) to document functional requirements. Scenarios can be represented in a variety of ways, from informal narratives through (formal) linear event sequences.