Brown Stairs are a collection of 10 brown exquisitely made cuboids in solid mango wood coated with brown non-toxic water-based stainers showing how the width and height can alter the length to stay the same. The height and width of the rectangular prisms range from 1 cm to 10 cm while the length stays constant at 20 cm. The cuboids are carved with incredibly accurate measurements.

Understanding the visual and skeletal sense of proportions is made easier by the material. As the child progresses to the mathematical elements that are a part of the Montessori environment, it gives a foundation for arithmetic learning in terms of numbers 1–10.