When you think about networks, you probably imagine all the different ways people use them. But what are networks really? What do they look like? And how can you make sense of them? As it turns out, there’s a simple image that can help answer all of those questions.

Networks can look like anything.

Networks are everywhere. They can be physical, virtual or conceptual. They can be made of people, computers or other things like ideas, energy and water. Networks can be highly structured and organized or very loose and chaotic; they may have formal rules (like laws) or informal ones (like social norms).

Network diagrams have a universal structure.

The structure of a network diagram is simple and universal. The nodes, or vertices, are represented by circles and the links between them are drawn as lines. Most diagrams also have an arrow at one end of each link to …