minecraft-assets/data/minecraft/recipe/green_carpet.json

{
  "type": "minecraft:crafting_shaped",
  "category": "misc",
  "group": "carpet",
  "key": {
    "#": "minecraft:green_wool"
  },
  "pattern": [
    "##"
  ],
  "result": {
    "count": 3,
    "id": "minecraft:green_carpet"
  }
}