<link href="//maxcdn.bootstrapcdn.com/bootstrap/4.1.1/css/bootstrap.min.css" rel="stylesheet" id="bootstrap-css">
<script src="//maxcdn.bootstrapcdn.com/bootstrap/4.1.1/js/bootstrap.min.js"></script>
<script src="//cdnjs.cloudflare.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
<!------ Include the above in your HEAD tag ---------->
<div class="container">
<div class="row">
<h2>Stickers</h2>
</div>
<div class="row">
<div class="col-sm-3">
<div class="bg-warning sticker">
<div class="">Orange Sticker</div>
</div>
</div>
<div class="col-sm-3">
<div class="bg-primary sticker">
<div class="">Blue sticker</div>
</div>
</div>
<div class="col-sm-3">
<div class="bg-success sticker">
<div class=""> Green Sticker</div>
</div>
</div>
</div>
</div>
.sticker{
min-height:300px;
box-shadow: 5px 5px 2px rgba(33, 33, 33, 0.7);
position: relative;
-webkit-box-shadow: 5px 5px 5px rgba(0,0,0,0.8);
-moz-box-shadow: 5px 5px 5px rgba(0,0,0,0.8);
box-shadow: 5px 5px 5px rgba(0,0,0,0.8);
padding:50px 0px 50px 50px;
color:#fff;
}
.sticker:before {
content: "";
position: absolute;
background:#fff;
top: 0%;
left: 0%;
width: 0px;
height: 0px;
border-bottom: 50px solid #eee;
border-left: 50px solid transparent;
-webkit-box-shadow: 7px 7px 7px rgba(0,0,0,0.3);
-moz-box-shadow: 7px 7px 7px rgba(0,0,0,0.3);
box-shadow: 7px 7px 7px rgba(0,0,0,0.3);
}