In the course of a single day, Youngest demonstrated that....
He'd figured out that if he jumped up and down on the pedal, he could open the baby gate that keeps him out of the kitchen.
He was tall enough to reach the hook and eye that keeps him out of the hall closet.
He'd figured out that if he piled a bunch of large, picture books he could build a platform that would let him reach the drawer where we keep little things, like batteries.
I'm pleased by his problem solving skills, less pleased by the uses to which he puts them.
There will come a day, probably not too far from now, when he can be reasoned with. When I can explain to him why he shouldn't draw on the walls, or put batteries in his mouth, or plays with knives, and he'll actually listen. I talk right now, and he grins, and he giggles, and he tries to grab the pencil/battery/knife back out of my hand.
But you know, that day can't possibly come soon enough.