Principles of Mechanical and Structural Engineering. The ideal educational building set for all future mechanical engineers, technicians and engineers: How does a shaft drive or a gearbox work? What is a planetary gear? How do you build a stable bridge? This educational building set containing 30 different models helps you to answer these and other fundamental questions from the world of mechanics and structural engineering. The eLearning portal ( fischertechnik-elearning.com) features engaging educational information and videos about mechanics and structural engineering.