{
  "type": "minecraft:overlay",
  "features": [
    {
      "feature": {
        "type": "minecraft:simple_block",
        "to_place": {
          "id": "minecraft:tube_coral_block"
        }
      },
      "placement": []
    },
    {
      "feature": "minecraft:coral/block_decoration",
      "placement": []
    }
  ]
}