Lucy: Listen, don't let Grandma Lewis fool you. Yes sir! You never know what's in a box by the wrapper.
Ricky: Well, really, I didn't even look at her wrapper.
Lucy: I didn't mean that. It's just an expression. It means just because there isn't any fire on a roof that there is no snow in the furnace.
Lucy: (thinks about what she said) It sounded better when she said it.