JSFiddle - React, Tailwind, and code Playground

HTML

<div></div>

CSS

div { 
    width: 100px;
    height: 100px;
    overflow: hidden;
    position: relative;
    background: red;
}

div:before {
    content: "";
    left: -15px;
    top: -15px;
    position: absolute;
    display: block;
    width: 30px;
    height: 30px;
    background: blue;    
}