{
  "structures": [
    {
      "structure": "minecraft:trial_chambers",
      "weight": 5
    },
    {
      "structure": "minecraft:ancient_city",
      "weight": 2
    }
  ],
  "placement": {
    "type": "minecraft:random_spread",
    "spacing": 5,
    "separation": 3,
    "salt": 33333333,
    "spread_type": "linear"
  }
}