[ksa]

Такой вот шахер-махер предложу...

<style type='text/css'>
div {
	width: 100px;
	height: 100px;
	margin: 100px;
	background-color: green;
}
div:before,
div:after {
	content: '';
	display: block;
	position: relative;
	left: -10px;
	background-color: red;
}
div:before {
	top: -10px;
	width: 50px;
	height: 10px;
}
div:after {
	top: -20px;
	width: 10px;
	height: 50px;
}
</style>
<div></div>