Develop focus and precision! Master each of the four challenge levles or mix the laters to create unique towere. Our exclusive Spring Blocks are ideal for building stable and dynamic structures. Each later card is printed with shapes that guide children while building. Check out our instructional video for suggestions. Includes: 24 Spring Blocks, 1 x 1 1/4x 21/2" (2.5 x 3 x 6.5cm), 28 layer cards up to 63/4 x 63/4" (17cm).