JSFiddle - React, Tailwind, and code Playground

HTML

<div></div>

CSS

body {
    background: #eee;
}

div {
    position: relative;
    height: 100px;
    width: 200px;
    background: #7b6f57;
}

div:before {
    content: '';
    position: absolute;
    display: block;
    top: 40px;
    right: -10px;
    width: 20px;
    height: 20px;
    -webkit-transform: rotate(45deg);
    transform: rotate(45deg);
    background: #eee;
}
div:after {
    content: '';
    position: absolute;
    display: block;
    top: 38px;
    right: -5px;
    width: 20px;
    height: 21px;
    -webkit-transform: rotate(45deg);
    transform: rotate(45deg);
    background: transparent;
    border-left: 2px solid #e5e2dd;
    border-bottom: 2px solid #e5e2dd;
}