This example shows a tree diagram where nodes are grouped into containers, each with a header, a body, and a footer. The container’s header and footer use custom GoJS shapes, `RoundedTopRectangle` and `RoundedBottomRectangle`, from the `RoundedRectangles` extension, while the body holds child nodes via a `Placeholder`. Node templates similarly combine these shapes to display role-based coloring and optional loop indicators using `BpmnActivityLoop`. The diagram uses `go.TreeLayout` for automatic positioning, and links are drawn with orthogonal routing and triangular arrowheads. Data is provided as a static JSON-like array of nodes and groups.