JSFiddle - React, Tailwind, and code Playground

HTML

<div class="bloc">
    <div class="bloc-border"></div>
</div>

CSS

.bloc
{
    position: relative;
    
    width: 35px;
    height: 80px;
    
    border: 1px solid #000;
}


.bloc-border
{
    display: block;
    position: absolute;
    
    width: 35px;
    height: 50px; 
    margin: -1px 0 0 -1px;
    
    border: 1px solid transparent;
    border-bottom: 1px solid #000;
    border-radius: 0 0 0 50px;
}


.bloc:before
{
    content: '';
    
    display: block;
    position: absolute;
    
    width: 35px;
    height: 50px; 
    margin: -1px 0 0 -1px;
    
    border: 1px solid #fff;
    border-radius: 0 0 0 50px;
}