time_units: generations
demes:
  - name: alpha
    epochs: 
      - start_size: 1000
  - name: beta
    epochs: 
      - start_size: 1000
  - name: gamma
    epochs: 
      - start_size: 1000
  - name: delta
    epochs: 
      - start_size: 1000
migrations:
  - demes: [alpha, beta, gamma, delta]
    rate: 1e-4