time_units: generations
demes:
- name: d0
  epochs:
  - {start_size: 1000}
- name: d1
  epochs:
  - {start_size: 1000}
- name: d2
  epochs:
  - {start_size: 1000}
- name: d3
  epochs:
  - {start_size: 1000}
pulses:
- {sources: [d0, d1], dest: d2, proportions: [0.1, 0.1], time: 100}