{
    "description": "circular definitions",
    "schema": {
      "definitions": {
        "a": {
          "properties":{
           "prop3":{"$ref": "#/definitions/b"}
            }
        },
        "b": {
          "properties":{
            "prop2":{"$ref": "#/definitions/a"}
           }
        }
      },
      "type": "object",
      "properties":{
        "prop1":{"$ref": "#/definitions/b"}
      }
    }
}