Another kind of tsumiki (in Japanese, literally "building blocks"), made with differently shaped tridimensional blackboards.
Not simply a game, but a clever and playful way to develop creativity, writing and drawing, while shaping and building forms. Manufactured by the same, remarkable factory near Tokyo, where people with intellectual disability are employed to work in a special environment specifically designed, it includes its own set of chalks, a pencil sharpener and a mini duster.