A surprisingly wide range of drawings are in essence composed of connected nodes. In an organisation chart, a node is a person, job function or organisation subgroup. The arrangement and connections show the hierarchy, reporting structure, or other interactions.
Organisations and their activities are often represented using connected nodes. Project plans, time-lines and dependencies, business processes, reporting and communications structures all take this form.
Many diagrams are composed of functional blocks with inputs and outputs. Examples are flowcharts, system diagrams and process illustrations. Schematics for electrical, electronic, plumbing, pneumatic and hydraulic systems all have broadly this form.
Software design makes increasing use of connected drawings. And tree structures also come under this category, as do network diagrams and topologies.