The layout sample highlights two areas or RadDiagram which are somewhat hidden in the API although it comprises a considerable amount of code and power:

- the graph analysis API which implements the typical graph algorithms
- the graph layout API which auto-organizes a graph 

The sample allows you to:

- create random graphs and visualize them. The code shows you how various methods are available in RadDiagram to create (pseudo-random) graphs with certain constraints like connectedness, tree-connected, single component, incidence constraints and so on.
- see how certain parameters affect the graph layout and how different layout algorithms give a different result
- see how certain well-known questions about graphs can be answered using the graph API; what is the shortest path between two nodes, what is a spanning tree in a graph, what is the longest routed between nodes, how many components does the graph have...and more.
- understand the generic way to approach graph analysis using RadDiagram

While this sample is certainly not a full application examplifying a graph-theoretic textbook it is a stepping stone if you wish to go into this direction. 