minecraft-assets/assets/minecraft/blockstates/deepslate.json

{
  "variants": {
    "": [
      {
        "model": "minecraft:block/deepslate"
      },
      {
        "model": "minecraft:block/deepslate_mirrored"
      },
      {
        "model": "minecraft:block/deepslate",
        "y": 180
      },
      {
        "model": "minecraft:block/deepslate_mirrored",
        "y": 180
      }
    ]
  }
}