Tonight I read Charlie The Snowy Day. Towards the end of the book, the boy puts a snowball in his pocket and goes inside only to find it is gone later. This was our conversation.

Charlie: Why was his snowball gone?
Me: Well, if you put a snowball in your pocket and brought it inside, do you think it would be there later?
Charlie: No.
Me: Why not?
Charlie: (with a little smile and look of knowing in his eye, leading me to believe he had come up with the answer) Because some bad guys will come and take it away.