JSFiddle - React, Tailwind, and code Playground

HTML

<div id="one"></div>
<div id="two"></div>

CSS

div {
    width: 80px;
    height: 80px;
    background: black;
    margin: 60px;
    position: relative;
}

#one:before {
  content: "";
  display: block;
  position: absolute;
  border-radius: 55%;
  width: 80px;
  height: 80px;
  background: black;
  left: 0;
  top: -34px;
}