How can teams make informed decisions today for systems that will emerge in the distant future? This paper explores the role of tangible systems prototypes in bridging the gap between speculation and interactive scenario development for complex product and service systems. Drawing from multiple fields, our study leverages Foresight Engineering, an approach pioneered at Stanford University that applies the practices of future studies and tangible prototyping to new technology and product development with the intent to make critical, forward-looking decisions. Five years of empirical data—including tangible artifacts, videos, photos, and narratives—were collected from teams employing low-fidelity systems prototyping and foresight engineering. Our findings reveal that this integrated approach enables teams to quickly embody complex future scenarios, simplify inherent complexity into tangible objects, and promote iterative discussions. The outcome is the generation of testable questions and the exploration of uncharted directions within the related opportunity and invention space. As the need intensifies to model, measure, and construct complex systems for a resilient and sustainable future, a Foresight Engineering approach empowers diverse teams to transition from the unknown (or unknowable) to actionable invention and the advancement of both knowledge and practice.