chromium/third_party/blink/web_tests/fast/css/background-clip-radius-values.html

<html>
<head>
<title>Testing Background clip values</title>
<style type="text/css">
div {
    display:inline-block;
    border: 10px solid rgba(128, 64, 64, 0.4);
    border-radius: 10px 30px;
    background-color:green;
    width: 100px;
    height: 100px;
    padding: 10px;
    margin: 10px;
}

.content-box {
   background-clip: content-box;
}
.padding-box {
   background-clip: padding-box;
}
.border-box {
   background-clip: border-box;
}

.tl {
    border-top-left-radius: 500px;
}

.tr {
    border-top-right-radius: 500px;
}

.bl {
    border-bottom-left-radius: 500px;
}

.br {
    border-bottom-right-radius: 500px;
}

.bigradii {
    border-top-left-radius: 130px 50px;      
    border-bottom-left-radius: 50px 50px;
    border-top-right-radius: 10px 50px;
    border-bottom-right-radius: 50px 50px;
}
</style>
</head>
<body>
<div class="content-box"></div>
<div class="padding-box"></div>
<div class="content-box tl br"></div>
<div class="padding-box tl br"></div>
<br>
<div class="content-box tr bl"></div>
<div class="padding-box tr bl"></div>
<div class="content-box tl"></div>
<div class="padding-box br"></div>
<br>
<div class="content-box tr"></div>
<div class="padding-box bl"></div>
<div class="content-box bigradii"></div>
<div class="padding-box bigradii"></div>
</body>
</html>