css/css-backgrounds/background-clip/clip-border-area-background-geometry-ref.html

<!DOCTYPE html>
<html>
<head>
<style>
    .test {
        margin: 20px;
        width: 300px;
        height: 200px;
        box-sizing: border-box;
        border: 50px solid transparent;
        background-image: url(../resources/stripes-100.png);
        background-size: 100px 100px;
        background-position: 15px 20px;
    }

    .test > div {
        width: 100%;
        height: 100%;
        background-color: white;
    }
</style>
</head>
<body>

<div class="test"><div></div></div>

</body>
</html>