Ravensburger's Gravitrax Starter Set is all you need to get started building these futuristic marble runs. With as many setups as you can dream up, Gravitrax is a great toy for creative expression and teaching STEM skills! Kids and adults can use the accompanying app to plan out their more ambitious builds, or follow included instructions. See how many divergent routes you can add, or time multiple paths to see which is fastest!ÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂ