{
  "structures": [
    {
      "structure": "lifesteal:example_1",            //<= structure
      "weight": 1                                    //<= weight
    },
    {
      "structure": "lifesteal:example_2",            //<= next structure
      "weight": 1                                    //<= weight
    }
  ],
  "placement": {
    "type": "minecraft:random_spread",                          //<= "random_spread" or "concentric_rings" (Use for strongholds). In most cases: "random_spread"
    "spacing": 50,                                              //<= Roughly the average distance in chunks between two structures in this set.
    "separation": 40,                                           //<= The minimum distance in chunks. Needs to be smaller than spacing.
    "salt": 1542327654                                          //<= unique identifier
  }
}
