Border With a Square - css

Question

How do I add a square onto a border between a div and an image? The square will be position on the left or the right depending on the position of the text (if the text is aligned right, the square will be bottom left; if the text is aligned left, the square will be top right).
.item {
flex: 1;
background: #8d0700;
margin-left: 5px;
margin-right: 5px;
padding: 0px;
width: 250px;
border: 5px solid #000;
}
.image img {
width: auto;
height: 450px;
outline: 2px solid rgba(218, 236, 255, 0.6);
outline-offset: -6px;
}
.name {
height: 100px;
text-overflow: wrap;
background-color: #8d0700;
color: #fff;
}
.bottomborder {
border-bottom: 5px solid #000;
}
.topborder {
border-top: 5px solid #000;
}
.name .left {
padding-left: 10px;
}
.name .right {
float: right;
margin-right: 10px;
}
<link href="https://www.w3schools.com/lib/w3.css" rel="stylesheet" />
<div class="w3-container w3-row-padding indexcontainer">
<div class="items">
<div class="w3-col l3 item">
<div class="name bottomborder">
<h3 class="right">Die Casting and Machining</h3>
</div>
<div class="image">
<img src="http://via.placeholder.com/200x200">
</div>
</div>
<div class="w3-col l3 item">
<div class="image">
<img src="http://via.placeholder.com/200x200">
</div>
<div class="name topborder">
<h3 class="left">Plastic Injection Products</h3>
</div>
</div>
</div>
</div>

Answer 1

You can achieve this using pseudoelements.
You can adjust the position as you need. I've used calc() here to take into account the width of the border.
.item {
flex: 1;
background: #8d0700;
margin-left: 5px;
margin-right: 5px;
padding: 0px;
width: 250px;
border: 5px solid #000;
}
.image img {
width: auto;
height: 450px;
outline: 2px solid rgba(218, 236, 255, 0.6);
outline-offset: -6px;
}
.name {
height: 100px;
text-overflow: wrap;
background-color: #8d0700;
color: #fff;
}
.bottomborder:after,
.topborder:before {
content: '';
width: 3em;
height: 3em;
background: black;
transform: rotate(45deg);
position: absolute;
}
.bottomborder {
border-bottom: 5px solid #000;
position: relative;
}
.bottomborder:after {
left: 3em;
bottom: calc(-1.5em - 3px);
}
.topborder {
border-top: 5px solid #000;
position: relative;
}
.topborder:before {
right: 3em;
top: calc(-1.5em - 3px);
}
.name .left {
padding-left: 10px;
}
.name .right {
float: right;
margin-right: 10px;
}
<link href="https://www.w3schools.com/lib/w3.css" rel="stylesheet" />
<div class="w3-container w3-row-padding indexcontainer">
<div class="items">
<div class="w3-col l3 item">
<div class="name bottomborder">
<h3 class="right">Die Casting and Machining</h3>
</div>
<div class="image">
<img src="http://via.placeholder.com/200x200">
</div>
</div>
<div class="w3-col l3 item">
<div class="image">
<img src="http://via.placeholder.com/200x200">
</div>
<div class="name topborder">
<h3 class="left">Plastic Injection Products</h3>
</div>
</div>
</div>
</div>