Diagrammatic, photographic, or actual material.

Examples of diagrammatic material include flowcharts, graphs, and maps.

Photographic material includes images, pictures, and photographs.

Actual material refers to physical objects or samples that can be touched and examined, such as a piece of fabric or a model of a building.

Diagrammatic:

- Flowcharts
- Diagrams
- Schematics
- Site maps
- Organizational charts
- Venn diagrams

Photographic:

- Still images
- Videos
- Time-lapse photography
- Aerial photography
- Microscopes and telescopes
- X-rays

Actual material:

- Physical objects (e.g., artifacts, specimens)
- Models (e.g., architectural models, scale models)
- Prototypes
- Simulator equipment
- Tools and equipment
- Product samples