The Cone (A050-4) is a solid geometric form used in the sensorial curriculum to support children's tactile and visual exploration of three-dimensional shapes, typically introduced in the primary environment alongside the other geometric solids. It allows children to isolate the concept of a cone's unique properties — its single circular base, curved surface, and pointed apex — through direct handling and comparison with forms like the cylinder and pyramid. Teachers restocking or completing a geometric solids set will find this individual piece essential for maintaining the integrity of the material's full presentation.