ethereal,
<!DOCTYPE html>
<html>
<head>
<title>Untitled</title>
<meta charset="utf-8">
<style type="text/css">
body{
display: flex;
flex-wrap: wrap;
justify-content: space-between;
margin: 0;
}
div {
height: 27vh;
border: 5px solid #FF8C00;
background-color: #32CD32;
width: 60vw;
margin: 10px;
}
div:nth-child(3n + 1), div:nth-child(4n + 1) {
width: 32vw;
background-color: #FF8C00;
}
</style>
</head>
<body>
<div></div>
<div></div>
<div></div>
<div></div>
<div></div>
<div></div>
</body>
</html>