<!DOCTYPE html>
<html lang="en-US">
<head>
<style>
#point:after{
content:"\021B9";
}
</style>
</head>
<body>
<p>BiDirectional Arrow Block using Hexa Decimal: ↹</p>
<p>BiDirectional Arrow Block using HTML Code: ↹</p>
<p id="point">BiDirectional Arrow Block using CSS Entity: </p>
</body>
</html>