Edit in JSFiddle

body {
background-color:#556;
background-image: linear-gradient(30deg, #445 12%, transparent 12.5%, transparent 87%, #445 87.5%, #445),
linear-gradient(150deg, #445 12%, transparent 12.5%, transparent 87%, #445 87.5%, #445),
linear-gradient(30deg, #445 12%, transparent 12.5%, transparent 87%, #445 87.5%, #445),
linear-gradient(150deg, #445 12%, transparent 12.5%, transparent 87%, #445 87.5%, #445),
linear-gradient(60deg, #99a 25%, transparent 25.5%, transparent 75%, #99a 75%, #99a), 
linear-gradient(60deg, #99a 25%, transparent 25.5%, transparent 75%, #99a 75%, #99a);
background-size:80px 140px;
background-position: 0 0, 0 0, 40px 70px, 40px 70px, 0 0, 40px 70px;
}