css - How to style a list ul to be a square -

i have ul

 <ul> <li>image</li> <li>image</li> <li>image</li> </ul> 

does know how css ul suare that? http://i.stack.imgur.com/7mqji.jpg

how this

ul{      width:300px;      list-style:none;  }  ul li:nth-child(1){      height:210px;  }  ul li{      float:left;      display:inline-block;      width:100px;      background:orange;      height:100px;      margin:5px;  }

<ul>  <li>image</li>  <li>image</li>  <li>image</li>  </ul>