JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css">
<div class="container">
    <div class="row">
        <div class="col-sm-4">
        Content 1
        </div>
        <div class="col-sm-4">
        Content 2<br>
        Content 2<br>
        Content 2
        </div>
        <div class="col-sm-4">
        Content 3
        </div>
        <div class="col-sm-4">
        Content 4
        </div>
        <div class="col-sm-4">
        Content 5
        </div>
        <div class="col-sm-4">
        Content 6
        </div>
        <div class="col-sm-4">
        Content 7
        </div>
    </div>
</div>

CSS

.col-sm-4 {
  border: 1px dashed skyblue;
}
.col-sm-4:nth-child(3n+1) {
  clear: left;
}