.container {
  position: relative;
  display: inline-grid;
  background: white;
  background-size: 6px 6px;
  background-position: 0 0, 0 15px, 15px -15px, -15px 0;
  background-image: linear-gradient(
      45deg,
      rgba(0, 0, 0, 0.15) 25%,
      transparent 25%
    ),
    linear-gradient(-45deg, rgba(0, 0, 0, 0.15) 25%, transparent 25%),
    linear-gradient(45deg, transparent 75%, rgba(0, 0, 0, 0.15) 75%),
    linear-gradient(-45deg, transparent 75%, rgba(0, 0, 0, 0.15) 75%);
}