minecraft-assets/data/minecraft/worldgen/template_pool/pillager_outpost/towers.json

{
  "elements": [
    {
      "element": {
        "element_type": "minecraft:list_pool_element",
        "elements": [
          {
            "element_type": "minecraft:legacy_single_pool_element",
            "location": "minecraft:pillager_outpost/watchtower",
            "processors": "minecraft:empty",
            "projection": "rigid"
          },
          {
            "element_type": "minecraft:legacy_single_pool_element",
            "location": "minecraft:pillager_outpost/watchtower_overgrown",
            "processors": "minecraft:outpost_rot",
            "projection": "rigid"
          }
        ],
        "projection": "rigid"
      },
      "weight": 1
    }
  ],
  "fallback": "minecraft:empty",
  "name": "minecraft:pillager_outpost/towers"
}