This is a set of 10 brown cuboids that demonstrates changes in 2 dimensions, ie, width and height, while the length remains constant. The rectangular prisms vary in area from 1cm2 to 10 cm2 while the length remains unchanging at 20cm. Each stair represents a number in the progression of 1cm2. Wood The wood prisms demonstrate to the child the change in the width (breadth), while the length of 20 cm, remains constant. Further practice with the broad stair indirectly prepares the child for concepts in plain geometry. Through tactile and visual discrimination, we have a full understanding of the differences in perceptual differences; develop coordination of eye, hand, and muscle movements, understand the relationship between progression and decline; learn the concept of cuboid; and cultivate logical thinking (sequence) And focus on observation. This teaching aid can be used with the Pink Tower! You can visit https://www.montessorialbum.com/montessori/index.php/Broad_Stair to know more about how to use this product