A river and its changing banks.
Blue water follows a winding river. The small brown and gray squares are colony cells: simple model patches whose survival depends on nearby cells and local water flow.
The cells can redirect water. Water can help cells survive, remove them, or support new cells nearby. This repeating loop is called feedback.
Starting with three small groups of colony cells.
Try this: let the river run for about a minute. Watch the three starting groups change. Use Pause and Step once to see one change at a time, or use Replay this start to begin again with the same starting cells.
The winding river is part of the starting landscape. The changing colony pattern is produced by the model's rules.
Try a small experiment
Turn the cells' effect on water off, then replay the same start. Compare the colony counts and patterns with a run where this effect is on. Water still affects the cells in both cases.
How the rules work
- Water enters at the top, with smaller flows entering from both upper sides.
- Colony cells increase resistance, so some water flows around them.
- Routes used repeatedly become more attractive to later flow.
- A cell survives only when it has suitable neighbors and a suitable amount of water flow.
- At most two new cells appear in each model step. A model step usually takes about one second at normal speed.
This is a simplified river and colony model, based on the earlier River-Colony Emergence v10 demonstration. It is not calibrated to a real river, plant species, or physical time scale. The moving water marks illustrate the calculated flow; each mark is not a measured volume of water.
How this uses Gongjing
The Gongjing core is the software that controls this model. It uses the same set of commands to start a world, advance time, read results, describe rules, make a change, and summarize larger patterns. The river's own rules are kept in a separate model module.
The controls on this page call that core directly. The calculation and animation run in your browser. This demonstrates a working software interface that other scientific models could also use.