Rainbow Nesting Arch Red (6pc)Ocamora Nesting Arch Red (6pcs). The nesting arch is one of the most versatile wooden toys as it serves to stack, fit, and build. You can start using it early and as the game evolves, you will find more and more possibilities. In the Montessori Pedagogy it is used to classify colors and sizes. The nesting arch is a self correcting element, which means that you will tend to place it in the right place using the trial error method, favoring such