JSFiddle - React, Tailwind, and code Playground

HTML

<div id="thing"></div>

CSS

#thing {
    height: 500px;
    background-image: linear-gradient(
        to right top,
        transparent 0%,
        transparent 33%,
        black 33%,
        black 66%,
        transparent 66%,
        transparent 100%
    );
    background-size: 3px 3px;
    
}