.carre1 {
	width:200px;
    height: 200px;
	position: absolute;
    top: 0;
    left: 0;
	background-color: grey;
}

.carre2 {
	width:200px;
    height: 200px;
	position: absolute;
    top: 0;
    right: 0;
	background-color: green;
}

.carre3 {
	width:200px;
    height: 200px;
	position: absolute;
    bottom: 0;
    right: 0;	
	background-color: purple;
}

.carre4 {
	width:200px;
    height: 200px;
	position: absolute;
    bottom: 0;
    left: 0;
	background-color: red;
}