Maps in My Head

Tonight at dinner Jerry informed us, "I have a map in my head!"
Mariah was pleased to hear this and replied, "I don't have a map in my head! You can use your map for me and Zach if we ever get lost."
Zach, either oblivious to the fact that Jerry's maps were in his head or just trying to find a way to join the conversation, piped in, "I have a Pensylvania map and a Michigan map."
Not to be outdone Jerry let us know that he actually had three maps in his head!
Jerry proudly stated, "I have one of Michigan, one to our house and one to Mamaws house, all in my head!"