The pink tower has ten pink cubes of different sizes, from 1 centimeter up to 10 cm in increments of 1 cm. The work is designed to provide the child with a concept of “big” and “small.” The child starts with the largest cube and puts the second-largest cube on top of it. This continues until all ten cubes are stacked on top of each other. The control of error is visual. The child sees the cubes are in the wrong order and knows that they should fix them. The successive dimensions of each cube are such that if the cubes are stacked flush with a corner, the smallest cube may be fit squarely on the ledge of each level.