https://blog.faceutil.com/2017/04/30/mame-%eb%8d%94%eb%b8%94-%eb%94%9c%eb%9f%ac-double-dealer-%eb%8b%a4%ec%9a%b4-%eb%8b%a4%ec%9a%b4%eb%a1%9c%eb%93%9c-down-%cf%80/