The Schelling model is a simple agent-based model that demonstrates how individuals’ relocation decisions can generate residential segregation in cities. In this model, agents belong to one of two groups and occupy cells of rectangular space. A cell can be occupied by a single agent only. Agents are able to relocate according to the fraction of friends (i.e., agents of their own group) within a neighbourhood around their location.

Here is a brief method for implementing a Schelling model with parameters Cells, threshold, vacancy, and mix:

1. Initialize the square grid with Reset. You can change the number of Cells, where each cell can be occupied by an agent of one of two groups, with ratio mix, or be vacant with probability vacancy.
2. For each agent, calculate the number of friends within its neighbourhood.
3. If the number of friends is below the threshold, the agent is unhappy and will relocate to a random vacant cell. (Each cell has at most 8 neighbours)
4. Press Step to run one iteration,Run to run the simulation, and Stop to end.(Some settings will lead to choas and never end!)
5. The simulation runs until no more unhappy agents exist.

This is just one way to implement a Schelling model with these parameters. There are many variations and extensions to this basic model that you can explore.