https://blog.wongcw.com/2020/09/16/%e5%ae%98%e7%b6%b2%e9%a1%af%e7%a4%basolo-loop%e7%b3%bb%e5%88%97%e9%8c%b6%e5%b8%b6%e9%81%a9%e7%94%a8%e6%96%bcseries-4%e5%8f%8a%e5%be%8c%e7%ba%8c%e7%89%88%e6%9c%ac%e7%9a%84apple-watch/