{
  "config": {
    "feature": {
      "config": {
        "feature": {your feature},
        "decorator": {
          "config": {},
          "type": "minecraft:square"
        }
      },
      "type": "minecraft:decorated"
    },
    "decorator": {
      "config": {
        "count": 3
      },
      "type": "minecraft:count"
    }
  },
  "type": "minecraft:decorated"
}