Have I ever mentioned that Truman loves to stack things? Seriously. As an infant, as soon as he learned to grab and move things, he began stacking them. He is a very, very mechanical child. He loves physics. When he gets a new toy he may enjoy what it does, but not as much as how it does it. It will be interesting to see how this passion of his develops as he gets older.
Grandma's floor level pantry cabinet always holds some good stacking material. I'm not even sure how this tower remained standing in the second picture. Seems to defy the laws of gravity.