div
{
	border: 2px solid black;
	position: absolute;
	box-sizing: border-box;
}

.roof
{
	background-color: lightblue;
	height: 481px;
	width: 481px;
	position: relative;
}

.green
{
	background-color: limegreen;
	height: 200px;
	width: 200px;
	left: 25px;
	top: 25px;
}

.blue
{
	background-color: royalblue;
	opacity: 0.8;
	height: 200px;
	width: 200px;
	left: 50px;
	top: 50px;
	z-index: 666;
}

.chocolat
{
	background-color: sienna;
	opacity: 0.8;
	height: 200px;
	width: 200px;
	left: 225px;
	top: 225px;
	z-index: 665;
}

.yellow
{
	background-color: yellow;
	opacity: 0.8;
	height: 200px;
	width: 200px;
	left: 250px;
	top: 250px;
	z-index: 0;
}