See, hear, touch and play with these fun, lightweight blocks specially designed with grooves for stacking up as high as you can build them. Then enjoy the crisp sounds they make as they topple over each other. Right side up, or upside down, the blocks are easily stackable into simple or complex forms, and are great for learning how different structures work together to support one another. Overlap different colors to explore color-mixing concepts, and then stack them up on our Light Cube for even more fun as you see your creations become brilliantly illuminated. Includes: 50 blocks, 2 x 2.5" (5 x 6 cm) and guide.