The Building Expansion offers over 25 additional elements to expand your track vertically. You’ll increase the action when increasing the height of your run. Experiment with the combination of height tiles, base plates, freefalls, switches and even another level. See how high you can build your track before getting the marbles to the finish. GraviTrax is a modular, electronic-free interactive track system where you can design and build your own marble runs. This STEM toy for boys and girls 8 and up, encourages experimenting with gravity, magnetism, and kinetics to propel your marble to the finish. Designed with open play in mind, the concept offers endless possibilities to design a different track every time you play. Expand your builds and add some action with a variety of expansion sets and accessories.