Expand your gravitrax starter-set with the building expansion pack. This kit lets you extend your run by combining additional base plates and other construction elements with your gravitrax starter-set. You'll be able to increase the possible combinations and construct even more complex systems. How many detours can you build in before the finish? With the gravitrax interactive track system, You can design and build your own race tracks and experiment with gravity, magnetism, and kinetics to propel your ball to the finish. With a variety of tiles, levels, tracks and features, you can control the speed of each ball. The open-ended building concept offers endless possibilities to design a different track every time you play. Add flair and speed to your tracks with expansion sets and action accessories. Experience the power of gravity with gravitrax.