Experience the power of gravity! GraviTrax is the STEM track system from Ravensburger! Use your imagination to build superb tracks and set the gravity spheres rolling! Create the element of surprise! Propel the action! Let the ball spin round and round with the Spiral. With different height possibilities, you can configure the Spiral to take the marbles on a dizzying journey from one level to another.This STEM system [Science, Technology, Engineering and Maths] is an ideal one to teach kids about gravity, magnetism, kinetic energy and fun. Hit a snag? Freestyle with your own track design or use the tasks and blueprints included to help you to get started in the world of GraviTrax! Are the gravity spheres stopping or flying off before reaching the end target? Time for some problem solving. Rebuild and try something different! The GraviTrax track system can be extended indefinitely with extra track packs and add-on’s – each sold separately.