JSFiddle - React, Tailwind, and code Playground

HTML

<div>

</div>

CSS

div{
  position:relative;
  left:20%;
  height:250px;
  width:150px;
  border:1px solid #000;
  top:10%;
  background:#fff;
}
div:before, div:after{
  position:absolute;
  content:'';
  left:-20px;
  border:10px solid transparent;
  border-right-color:#fff;
  top:30px;
}
div:after{
  left:-21px;
  border-right-color:#000;
  z-index:-1
}