<html>
<head>
<meta charset="UTF-8">
</head>
<style>
div{float:left;margin:0 40px;}
#div1{
width:0;
height:0;
border-top:40px solid black;
border-left:40px solid transparent;
border-right:40px solid transparent;
}
#div2{
width:0;
height:0;
border-left:40px solid red;
border-top:40px solid transparent;
border-bottom:40px solid transparent;
}
#div3{
width:0;
height:0;
border-bottom:40px solid blue;
border-left:40px solid transparent;
border-right:40px solid transparent;
}
#div4{
width:0;
height:0;
border-right:40px solid green;
border-top:40px solid transparent;
border-bottom:40px solid transparent;
}
</style>
</head>
<body>
<div id="div1"></div>
<div id="div2"></div>
<div id="div3"></div>
<div id="div4"></div>
</body>
</html>
