This is a project written in Swift 1.0 for iOS 8. It can be built and run with Xcode either in the simulator or on device (could be a bit slow).
The project builds and visualizes a graph of coaches and pupils. These are lovingly referred to in the code as Doyens (a somewhat antiquated word for an academic leader) and Abecedarians (possibly more obscure!). Primary coach/pupil relationships are drawn in solid grey, secondary coaching relationships are in dashed green. Due to the graph/tree nature of the code, it is quite recursion heavy.
The project lets you infect parts of the graph using the selected algorithm by tapping on a node. For the limted infection, you may adjust the slider to change the targeted number of infections. Infected persons have their node color change.
Enjoy!