<div class="rectangle">
<div class="square">
<div class="circle"><div>
</div>
</div>
<style>
body {
margin: 0px;
display: grid;
place-content: center;
background: #222730;
}
.rectangle {
width: 400px;
height: 150px;
background: #4CAAB3;
position: relative;
}
.square {
width: 150px;
height: 150px;
position: absolute;
transform: rotate(45deg);
top: -50px;
left: 75px;
border: 50px solid #222730;
background-color: #4CAAB3;
-webkit-backface-visibility: hidden;
}
.circle {
position: absolute;
background: #393E46;
width: 50px;
height: 50px;
top: 50px;
left: 50px;
border-radius: 50%;
}
</style>