<!DOCTYPE html>
<html>
    <head>
        <title>balancing fixed-height multicol</title>
    </head>
    <body style="overflow:hidden;">
        <p>There should be three identical blue rectangles below.</p>
        <div style="-webkit-columns:3; -webkit-column-gap:1em; columns:3; column-gap:1em; line-height:2em; height:3.9em; width:20em;">
            <div style="background:blue;"><br><br><br></div>
        </div>
    </body>
</html>