With the GraviTrax Pro Starter Set Extreme, children aged 8 and up can playfully experience the laws of gravity. More challenges, more possibilities, more fun. The Extreme Starter Set encourages the construction of extremely exciting and complex tracks. Four action stones from the Pro series create entirely new possibilities when combined. The optimal combination of classic GraviTrax stones and vertical elements in this set brings challenges and greater flexibility in building. How can the four action stones be combined in the most extreme way? With GraviTrax, building fun knows no bounds. The GraviTrax marble run system can be infinitely expanded with extensions, guaranteeing limitless building and play enjoyment. By freely designing the marble tracks and exploring the rolling and flying behavior of the marbles, understanding of science is sharpened, and gravity is made tangible. The STEM symbol on the products signals a game category where science is experienced in a playful way. STEM (Science, Technology, Engineering, Mathematics) corresponds to the German MINT (Mathematics, Computer Science, Natural Sciences, Technology).