Nesting Boxes offer a concrete, hands-on introduction to seriation and spatial reasoning for toddlers and young primary children working on order and size gradation. Unlike the Pink Tower, which builds vertically, nesting materials ask the child to coordinate size relationships in a contained, fitting motion that also develops hand strength and eye-hand coordination. This material works well on a low shelf in a toddler or early primary environment where children are just beginning to internalize the concept of biggest to smallest.