This interactive example presents a system dynamics diagram using the GoJS library, letting users add stocks, clouds, variables, and valves to model material flows. The interface offers modal creation tools: users click buttons to switch between pointer, node, and link modes for building flow and influence connections. The diagram supports saving and loading models as JSON via the `GraphLinksModel`, with custom templates built in `buildTemplates()`. Node and link styling is handled through GoJS’s `GraphObject.make`, and the `NodeLabelDraggingTool` extension enables label repositioning through mouse move tools.