<html>
<head>
<style>
body { background-color: black; }

.test {
    border-radius: 40px;
    -webkit-box-shadow: inset white 0 0 0 15px;
    border: 4px solid green;
    background-color: blue;
    margin: 20px;
}

#test0 {
    height: 70px;
    width: 70px;
    float: left;
}

#test1 {
    height: 100px;
    width: 70px;
    float: left;
}

#test2 {
    height: 70px;
    width: 100px;
    float: right;
}

#test3 {
    height: 100px;
    width: 100px;
    float: right;
}

</style>
</head>
<body>
<div>
  <div class="test" id="test0"></div>
  <div class="test" id="test1"></div>
  <div class="test" id="test2"></div>
  <div class="test" id="test3"></div>
</div>
</body>