Little E learned to stack things for the first time a couple of weeks ago. He found that my baking cupboard was the only one I couldn't tie, rubber band or block shut, so he gets into it all the time.
He also found out that that's where the chocolate chips are kept. He always rearranges everything that is on the shelves. For some reason he usually takes both cocoa tins out first, and then the vintage Tupperware canisters, then the plastic Costco jars. This day he took everything out and started to stack things on top of each other. I use the empty Costco jars for my coconut, brown sugar, etc. and he found out that they can also be used as fun stacking toys so he tried every combination possible to get his stack as high as he is tall. He managed to do it.