Grimm's | CornerstonesA building block that enables surprising and tricky laying variants and trains spatial thinking. In this way, new bodies in different colour patterns and shapes are created over and over again. In combination with our classic building materials, the cornerstones unfold their true size and can thus create unique marble runs. 18 building blocks in a wooden frame. Wood: lime wood, varnished in colour and oiled. Dimensions: length wooden frame 15cm,