*{margin:0;padding: 0;}
   li{list-style: none;}
   html,body{height: 100%;}
   body{perspective: auto;}/*设置3D景深*/
   .box1{
    width:200px;
    height:200px;
    position: absolute;
    left: 0;right: 0;top: 0;bottom: 0;margin: auto;/*使ul在屏幕正中的位置*/
    background: rgba(244,4,253,0.3);/*给ul一个紫色透明的背景*/
    transform-style:preserve-3d;/*定义ul的样式为3D属性*/
    animation: box 10s 0.3s linear infinite;
    }
   li{
    width: 200px;
    height: 200px;
    position: absolute;left: 0;top: 0;/*使6个li在屏幕正中位置的互相重叠*/
    font:50px/200px "微软雅黑";
    color: white;
    text-align: center;
    } 
   ul{
   transform: rotateY(20deg) rotateX(20deg)；/*让ul旋转一定的角度，方便观察各个面的变换效果*/
   }
html...............
<ul class="box1">
    <li>前</li>
    <li>后</li>
    <li>左</li>
    <li>右</li>
    <li>上</li>
    <li>下</li>  
</ul>  

           li:nth-child(1){
    background: #ff0;
    transform: translateZ(100px);
   }
   li:nth-child(2){
    background: #330;
    transform: translateZ(-100px) rotateY(180deg);
   }
   li:nth-child(3){
    background: #f00;
    transform: translateX(-100px) rotateY(-90deg);
   }
   li:nth-child(4){
    background: #0f0;
    transform: translateX(100px) rotateY(90deg);
   }
   li:nth-child(5){
    background: #0ff;
    transform: translateY(-100px) rotateX(90deg);
   }
   li:nth-child(6){
    background: #00f;
    transform: translateY(100px) rotateX(-90deg);
   }