css3 loading 效果2

代码：
<!doctype html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
<style>
#box{
    position: relative;
    width: 40px;
    height: 40px;
    margin: 100px;
}
#box span{
    display: block;
    width: 20px;
    height: 20px;
    position: absolute;
    bottom: 0;
    background-color: #9b59b6;
}
#box span:nth-child(1){-webkit-animation:preloader1 1.5s infinite ease-in-out;}
#box span:nth-child(2){-webkit-animation:preloader2 1.5s infinite ease-in-out;left: 20px;}
#box span:nth-child(3){-webkit-animation:preloader3 1.5s infinite ease-in-out;top: 0px;}
#box span:nth-child(4){-webkit-animation:preloader4 1.5s infinite ease-in-out;top: 0px;left: 20px;}
@-webkit-keyframes preloader1{
    0%{transform:translateX(0px) translateY(0px) rotate(0deg);border-radius: 0px;}
    50%{transform:translateX(-20px) translateY(-10px) rotate(-180deg);border-radius: 20px;background-color: #3498db;}
    80%{transform:translateX(0px) translateY(0px) rotate(-360deg); border-radius:0px;}
    100%{transform:translateX(0px) translateY(0px) rotate(-360deg); border-radius:0px;}
}
@-webkit-keyframes preloader2{
    0%{transform:translateX(0px) translateY(0px) rotate(0deg);border-radius: 0px;}
    50%{transform:translateX(20px) translateY(-10px) rotate(180deg);border-radius: 20px;background-color: #f1c40f;}
    80%{transform:translateX(0px) translateY(0px) rotate(360deg); border-radius:0px;}
    100%{transform:translateX(0px) translateY(0px) rotate(360deg); border-radius:0px;}
}
@-webkit-keyframes preloader3{
    0%{transform:translateX(0px) translateY(0px) rotate(0deg);border-radius: 0px;}
    50%{transform:translateX(-20px) translateY(10px) rotate(-180deg);border-radius: 20px;background-color: #2ecc71;}
    80%{transform:translateX(0px) translateY(0px) rotate(-360deg); border-radius:0px;}
    100%{transform:translateX(0px) translateY(0px) rotate(-360deg); border-radius:0px;}
}
@-webkit-keyframes preloader4{
    0%{transform:translateX(0px) translateY(0px) rotate(0deg);border-radius: 0px;}
    50%{transform:translateX(20px) translateY(10px) rotate(180deg);border-radius: 20px;background-color: #e74c3c;}
    80%{transform:translateX(0px) translateY(0px) rotate(360deg); border-radius:0px;}
    100%{transform:translateX(0px) translateY(0px) rotate(360deg); border-radius:0px;}
}
</style>
</head>
<body>
    <div id="box">
        <span></span>
        <span></span>
        <span></span>
        <span></span>
    </div>
</body>
</html>
效果图：
高否？富否？帅否？否？滚去学习！