chromium/third_party/blink/web_tests/external/wpt/css/css-flexbox/flexbox_columns.html

<!DOCTYPE html>
<title>flexbox | multicol</title>
<link rel="author" href="http://opera.com" title="Opera Software">
<link rel="help"
	href="http://www.w3.org/TR/css-flexbox-1/#flex-containers">
<link rel="match" href="flexbox_columns-ref.html">
<style>
ul {
	background: black;
	padding: 0;
	margin: 0;

	display: flex;
	justify-content: space-around;
	columns: 3;
	column-rule: 1em solid red;
}
::marker { font-family:inherit; }
</style>

<ul>
	<li>one two three four</li>
	<li>filler</li>
	<li>filler</li>
	<li>filler</li>
	<li>filler</li>
</ul>