<!DOCTYPE html>

<html>
<head>
    <style>
        .background {
            height: 100px;
            width: 100px;
            padding: 50px;
            background-image: repeating-linear-gradient(black 0px, black 25px, white 25px, white 50px);
            border: 1px solid black;
        }
        
        #box {
            height: 100px;
            width: 100px;
            -webkit-backdrop-filter: blur(20px);
        }
    </style>
</head>
<body>
<div class="background">
    <div id="box">
    </div>
</div>
</body>
</html>