.real{
display: flex;
 }
 .real-div{
  width: 250px;
  height: 250px;
 }
 .real-div:nth-child(1){
    position: relative;
    background-color: red;
 }
  .real-div:nth-child(2){
    position: relative;
    z-index: 1;
    top: 150px;
    left: -75px;
    background-color: blue;
 }
  .real-div:nth-child(3){
    position: relative;
    top: 300px;
    left: -150px;
    background-color: green;
 }