[
  {
    "type": "mapgen",
    "method": "json",
    "nested_mapgen_id": "crater_bomb",
    "object": {
      "mapgensize": [ 1, 1 ],
      "place_item": [ { "item": "crater_bomb", "x": 0, "y": 0, "custom-flags": [ "ACTIVATE_ON_PLACE" ] } ]
    }
  },
  {
    "type": "mapgen",
    "method": "json",
    "update_mapgen_id": "mx_crater",
    "object": { "place_nested": [ { "chunks": [ [ "crater_bomb", 100 ] ], "x": [ 0, 23 ], "y": [ 0, 23 ] } ] }
  }
]
