{
  "type": "minecraft:random_patch",
  "config": {
    "tries": 1,
    "xz_spread": 3,
    "y_spread": 2,
    "feature": {
      "feature": {
        "type": "minecraft:simple_block",
        "config": {
          "to_place": {
            "type": "minecraft:simple_state_provider",
            "state": {
              "Name": "minecraft:smooth_basalt"
            }
          }
        }
      },
      "placement": [
        {
          "type": "minecraft:block_predicate_filter",
          "predicate": {
            "type": "minecraft:all_of",
            "predicates": [
              {
                "type": "minecraft:matching_blocks",
                "blocks": [
                  "minecraft:air"
                ]
              },
              {
                "type": "minecraft:matching_blocks",
                "offset": [
                  0,
                  -1,
                  0
                ],
                "blocks": [
                  "minecraft:smooth_basalt"
                ]
              }
            ]
          }
        }
      ]
    }
  }
}
