{
  "$id": "https://example.com/polygon",
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$defs": {
    "point": {
      "type": "object",
      "properties": {
        "x": { "type": "number" },
        "y": { "type": "number" }
      },
      "additionalProperties": false,
      "required": [ "x", "y" ]
    }
  },
  "type": "array",
  "items": { "$ref": "#/$defs/point" },
  "minItems": 3
}