Add sound to your Quadrilla tracks with xylophone rails that play a scale as the marbles race over them. Play Tips Build the layout depicted on the box and connect it to an existing Quadrilla set. Listen for your marbles as they descend down the xylophone rails. Reverse the direction of the rails to play a different melody. Features • Marble track construction toy made from sustainable wood and non-toxic water-based paint • Includes 2 distribution blocks, 2 stabilizing rings, 8 marbles and a xylophone rail. • The xylophone rail plays as the marbles roll down • German-manufactured design inspired by the Da Vinci Circle • Helps develop spatial thinking and understanding of scientific, technological, architectural, artistic and mathematical (WTBAW) principles • Recommended by The Wall Street Journal as the perfect toy for teaching kids to code • Compatible with all Hape Quadrilla sets • Suitable for ages 4 and up