Once a child has mastered the visual discrimination materials in the Sensorial area (i.e. Pink Tower, Broad Stair, Red Rods, and Knobless Cylinders), they are free to explore different combinations. The children are building a holiday tree using all of the aforementioned materials. They are using their visual discrimination to lay the materials out in a sequential format (i.e. longest to shortest, widest to narrowest, etc.). Putting the materials in this sequential format creates the shape of a holiday tree.