JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://code.jquery.com/jquery-3.3.1.min.js"></script>
<div class="brick">
    <div class="blend S"></div>
    <div class="blend S"></div>
    <div class="blend S"></div>
</div>

CSS

.blend{
  width: 100px;
  height:25px;
}
.a01{
  background: red;
}

.a02{
  background: green;
}

.a03{
  background: blue;
}

.a04{
  background: yellow;
}

JavaScript

$(document).ready(function(){
var classes = ["a01", "a02", "a03", "a04"];
    $(".S").each(function(){
        $(this).addClass(classes.splice(Math.floor(Math.random() * classes.length), 1));
    });
});