<html>
    <head>
        <style type="text/css">
        #parent {
            -moz-transform-style: preserve-3d;
        }

        #one {
          width: 100px;
          height: 100px;
          background-color: #00FF00;
          -moz-transform: translatez(10px);
        }

        #two {
          width: 100px;
          height: 100px;
          background-color: red;
          -moz-transform: translatez(-10px) translatey(-50px);
        }
        </style>
    </head>
    <body>
        <div id="parent">
                <div id="one"></div>
                <div id="two"></div>
        </div>
    </body>
</html>