<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http:/html4/strict.dtd">
<html lang="en">
<head>
<style type="text/css">
.a {
background: green;
height: 30px;
width: 30px;
position: relative;
margin: 25px;
outline-color: red;
outline-style: auto;
}
.b {
background: blue;
height: 20px;
width: 20px;
top: 5px;
left: 5px;
position: relative;
}
.second {
margin-top: -5px;
}
</style>
</head>
<body>
<div class="a"><div class="b"></div></div>
<div class="a second"><div class="b"></div></div>
</body>
</html>