#A {
background-color: red;
width: 250px;
height: 250px;
font-size: 70px;
color: white;
text-align: center;
position: absolute;
top: 175px;
left: 200px;
z-index: 2;
}

#B {
background-color: greenyellow;
width: 250px;
height: 250px;
font-size: 70px;
color: white;
text-align: center;
position: absolute;
top: 275px;
left: 100px;
z-index: -1;
}

#C {
background-color: blue;
width: 250px;
height: 250px;
font-size: 70px;
color: white;
text-align: center;
position: absolute;
top: 325px;
left: 250px;
z-index: 1;
}