JSFiddle - React, Tailwind, and code Playground

HTML

<div id="container">
    <div class="b"></div><div class="b"></div><div class="b"></div><div class="b"></div><div class="b"></div><div class="b"></div><div class="b"></div><div class="b"></div><div class="b"></div><div class="b"></div><div class="b"></div><div class="b"></div><div class="b"></div><div class="b"></div><div class="b"></div><div class="b"></div><div class="b"></div><div class="b"></div><div class="b"></div><div class="b"></div><div class="b"></div>
</div>

CSS

#container {
    width: 304px;
    height: 200px;
    border: 1px solid gray;
}

.b {
    display: block;
    float: left;
    width: 16px;
    height: 16px;
    background: blue;
}