<div class="green-box">  </div>
<div class="pink-box">  </div>
<div class="blue-box">  </div>

div{
  width: 100px;
  height: 100px;
  border: 3px solid;

}

.green-box{
  background-color: green;
  position: relative;
}
.pink-box{
  background-color: hotpink;
  margin-top: -30px;
  margin-left: 20px;
}
.blue-box{
  background-color: blue;
  margin-top: -30px;
  margin-left: 40px;

}