<!DOCTYPE html>
<html>
<head>
<style>
div{
width:0px;
height:0px;
background: white;
}
#first{
border-top: 100px solid white;
border-right: 100px solid white;
border-bottom:100px solid green;
border-left: 100px solid white;
float:left;
}
#second{
width:0px;
height:100px;
border-top: 100px solid white;
border-right: 100px solid white;
border-bottom:100px solid green;
border-left:100px solid white;
}
#third{
width:20px;
height: 200px;
margin-left: 90px;
background: green;
}
</style>
</head>
<body>
<div id="contain">
<div id="first"> </div>
<div id="second"> </div>
<div id="third"> </div>
</div>
</body>
</html>
原文：http://www.cnblogs.com/jiangger/p/6439708.html