css实现圆形，三角形

圆形:
<style> #cir{ width:5px; height:5px; background-color: blue; border-radius:200px; -webkit-border-radius:200px; -moz-border-radius:200px; } </style>

三角形:
#cir{ width:0; height:0; border-color:red transparent transparent transparent; border-style:solid; border-width:20px; overflow:hidden; font-size:0; }
五角星: