https://blog.faceutil.com/2020/03/27/%ec%95%84%ec%9b%83-%ec%9b%8c%eb%93%9c-outward-v1-0-%ed%8a%b8%eb%a0%88%ec%9d%b4%eb%84%88-fling-18-%ed%95%9c%ea%b5%ad%ec%96%b4%eb%b2%84%ec%a0%84-%d0%b3/