Jade has a red "truck" that she loves to play with. On the front of the truck, there is a hood that, when you lift it up, says "Open" or "Up", and when you let it down, says, "Closed" or "Down". Very educational. The hood of the truck also has three holes in it; one for a round block, one for a square block, and one for a triangle block.
I was demonstrating to Jade how to put the round block into the round hole and the square block into the square hole. Inviting Jade to try, I handed her the triangle block.
She took the triangle block, lifted the hood of the truck, and tossed it in. Much easier than trying to fit it in through the little hole. Then, she turned to look at me with that expression of pity and scorn that she will have perfected by the time she becomes a teenager. You know, the one that means, "Dad, you are so stupid!" or "D'uh!" or a thousand variations of the same theme.
I supposed I had better get used to it.