JSFiddle - React, Tailwind, and code Playground

HTML

<div>1</div>
<div>2</div>
<div>3</div>

CSS

div {
    box-shadow: 0 0 10px rgba(0,0,0,0.5); 
    width:50px;
    background:red;
    height:400px;
    -webkit-border-bottom-right-radius: 100px 50px;
    -webkit-border-bottom-left-radius: 100px 50px;
    -moz-border-radius-bottomright: 100px 50px;
    -moz-border-radius-bottomleft: 100px 50px;
    border-bottom-right-radius: 100px 50px;
    border-bottom-left-radius: 100px 50px;
    /* добавлено */
    float: left;
    margin-left: -10px;
    /* можно удалить */
    color: #fff;
    font-size: 20px;
    text-align: center;
    line-height: 100px;
}