<html>
<head>
<style>
div.crossTop {
  height: 300px;
  width: 100px;
  background-color:green;
  display: -moz-box;
  display: -webkit-box;
  display: box;
  -moz-box-align: center;
  -webkit-box-align: center;
  box-align: center;
  -moz-box-orient: vertical;
  -webkit-box-orient: vertical;
  box-orient: vertical;
}

div.crossBar {
  height: 100px;
  width: 300px;
  background-color:green;
  margin-top: 100px;
  margin-left: -100px;
}
</style>
</head>
<body>
You should see a green cross below (300 pixels wide and 300 pixels tall).  This is a test to ensure that
boxes don't obey the overconstraint correction (margin-right/left should not be corrected when a box is
overconstrained). 

<div style="padding:100px">
<div class="crossTop">
<div class="crossBar"></div>
</div>
</div>
</body>
</html>