<!DOCTYPE html>

<html>
<head>
    <style>
        .box {
            position: absolute;
            top: 0;
            left: 0;
            height: 100px;
            width: 100px;
        }

        #animating {
            background-color: orange;
            z-index: 0;
        }

        .behind {
            background-color: blue;
            top: 50px;
            left: 50px;
            z-index: 1;
        }

        .front {
            top: 25px;
            left: 25px;
            background-color: green;
            z-index: 2;
        }
    </style>
</head>
<body>

<div class="behind box"></div>
<div id="animating" class="box">
    <div class="front box"></div>
</div>

</body>
</html>