index.html

<!DOCTYPE html>
<html>

<head>
	<title>Flexy box</title>
	<link rel="stylesheet" href="css/main.css">
</head>

<body>
	
	<div class="wrap">
		<div class="box"></div>
		<div class="box"></div>
		<div class="box"></div>
		<div class="box"></div>
		<div class="box"></div>
	</div>

	<div class="wrap">
		<div class="box"></div>
		<div class="box"></div>
		<div class="box"></div>
		<div class="box"></div>
	</div>

	<div class="wrap">
		<div class="box"></div>
		<div class="box"></div>
		<div class="box"></div>
		<div class="box"></div>
		<div class="box"></div>
		<div class="box"></div>
		<div class="box"></div>
		<div class="box"></div>
		<div class="box"></div>
		<div class="box"></div>
	</div>

	<div class="wrap">
		<div class="box"></div>
		<div class="box"></div>
		<div class="box"></div>
		<div class="box"></div>
	</div>

</body>

</html>