The Montessori School Brown Stair, or the Broad Stair, is meant to develop the child’s awareness of size difference. All ten blocks are the same length, but they vary in both length and depth. This material trains both the eye and the hand to discriminate and compare between wide and narrow. The Brown Stair is a grading activity that helps visual acuity and the concept of sequence in preparation for future activities, such as reading, writing, and math. Much like the Pink Tower, it helps kids with distinguishing the difference in the size of objects.