Example with all variables modifiable

leader:                       # A leadership
  - leader: value1            # A leader
    follower1: val11          # A follower
    follower2: val21          # An other follower
  - leader: value2            # A leader
    follower1: val11          # A follower
    follower2: val21          # An other follower
calculate:                    # A calculated variable
  - val11
  - val11