body {
    background-image:
      linear-gradient(45deg, yellow 25%, transparent 25%),
      linear-gradient(90deg, transparent 75%, steelblue 75%),
      linear-gradient(90deg, transparent 75%, sienna 75%),
      linear-gradient(90deg, sienna 50%, sienna 25%);    

    background-size:100px 100px;       

    background-position:0 0, 0 0, -50px -50px, 50px 50px;
}