.a, .b, .c, .d{
	float:left;
	width:200px;
	height:100px;
	position:relative;
	left:0;
}
.a{
	background:#f00;
}
.b{
	background:#0f0;
}
.c{
	background:#00f;
}
.d{
	background:#ff0;
}