We've all seen one-year-olds' pleasure in bashing down block towers. No sooner have you built it for them, when whack, they gleefully knock it down! It's amazing then to see them reach the next stage, when they start carefully stacking blocks up instead. Some also make horizontal rows on the floor, but this vertical phase seems universal. I guess it's that triumph of getting the blocks to stay in place and making something grow. It's exciting, because you know it's the first step toward constructions that will become increasingly imaginative and creative.
Twenty-month Brenna doesn't realise she is learning about balance and centre of gravity! What will she be building a year from now?