Rock Blocks were designed with asymmetrical shapes so you can build + balance towers, arches, mountains, letters, and shapes. Rock Blocks are not only a fun montessori challenge for kids, but also adults! -Open-Ended Play -Unplugged Toy: No batteries needed. -Captivating + Challenging -Child safe + non-toxic. -Handmade in Utah Every block is unique. The blocks shown will be different than the blocks you receive. Sizing can vary between a width/height of 1.5-2 inches.