1、图形
2、代码
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title></title>
<style>
.d{
width:0px;
height:100px;
border-left:25px solid;
border-top:25px solid transparent;
border-bottom:25px solid transparent;
}
</style>
</head>
<body>
<div class="d"></div>
</body>
</html>