I remember reading that Montessori once allowed the children to knock over the Pink Tower. She realised that this was damaging the cubes and put a stop to it. The Pink Tower is typically presented to children at 3-4 years and is a tower of ten cubes.

This is our toddler version, the coloured tower where knocking down is totally acceptable but deconstructing is preferred. 

I love the physicality of it. As Montessori said in the construction of the tower the child goes through the stages of kneeling and rising. It's also the movement of the child. As a toddler I think this helps refine their movements. Not only in constructing the tower but also in moving the cubes around, lifting, placing on the ground. This is a great activity for a child who has trouble sitting still.

Otis and I do this together. It's a load of fun.