Answer 1

.blue {
z-index: 3;
position: relative;
background-color: #8EC4D0;
margin-bottom: 15px;
width: 120px;
height: 120px;
color: #FFF;

}
.red {
z-index: 2;
position: relative;
background-color: #FF4D4D;
width: 120px;
height: 120px;
color: #FFF;
left: calc( 50% - 60px );
margin-top: -50px;
margin-left: 50px;

}