Oh, that explains it!

The other day we were all riding in Marc's car. It's something we rarely do as a family because Marc uses the car for work and it really doubles as his office. Andrew is in the back and pulls out a laminated map. This conversation followed:

Andrew (holding up the map): What's this?
Marc: A map.

Andrew: What does it do.
Marc: It shows you where to go.

Andrew: But how?
Marc: You read it and it tells you how to get where you need to go.

Andrew: But how?
Marc: It's like GPS.

Andrew: OH! Okay.