https://blog.wongcw.com/2020/03/19/a12z%e6%af%94a12x%e5%bc%b7%e5%a4%9a%e5%b0%91%ef%bc%9f%e8%b7%91%e5%88%86%e6%88%96%e8%a8%b1%e5%8f%af%e4%bb%a5%e5%91%8a%e8%a8%b4%e4%bd%a0/