"Ten wooden cubes colored pink. The sides of the cubes diminish from ten centimeters to one centimeter.
With these cubes the child builds a tower, first laying on the ground (upon a carpet) the largest cube, and then placing on the top of it all the others in their order of size to the very smallest.
As soon as he has built the tower, the child, with a blow of his hand, knocks it down, so that the cubes are scattered on the carpet, and then he builds it up again. " (p. 72)
This makes a lot of intuitive sense! But it's not popular with Montessori schools -- a combination of the high cost of equipment and the general desire to keep kids quiet. Not such a big problem for many children, but it seems especially unfair for children who are especially active or physical.
So, quote Maria Montessori to your child's teacher next time. For all your Montessori homeschoolers out here, keep up the good work!
The book, Dr. Montessori's Own Handbook, is, incidentally quite a good bargain because the language is a bit old-fashioned, it has an unglossy jacket cover, and the photos are in black and white. Since such things matter tremendously in book sales, you can find a used copy very cheaply!