JSFiddle - React, Tailwind, and code Playground

HTML

<div class="blocks">
    <div class="blocka" style="height:170px;">1</div>
    <div class="blocka" style="height:300px;">2</div>
    <div class="blocka" style="height:220px;">3</div>
    <div class="blocka" style="height:100px;">4</div>
    <div class="blocka" style="height:190px;">5</div>
    <div class="blocka" style="height:130px;">6</div>
</div>

CSS

.blocks {
	width: 310px;
}

.blocka {
	width: 150px;
	float: left;
	vertical-align: top;
	border: 1px solid red;
}