Intersection graph is a type of picture that shows how different things are related to each other. It looks like a bunch of circles (nodes) connected by lines (edges). Each circle represents something different, like a person, place, or thing. The lines show how the circles are connected. So if two circles have a line connecting them, it means that the two circles are related in some way. For example, if two circles represent two people, the line connecting them would show that they are friends.