<div class="example1">サンプル1</div>
<div class="example2">サンプル2</div>
<div class="example3">サンプル3</div>

body {
  padding: 10px 5%;
}
.example1,
.example2,
.example3 {
  padding: 30px;
  margin-bottom: 20px;
  text-align: center;
  position: relative;
}

/* example1 */
.example1::before {
  content: "";
  background-image: linear-gradient(to right, #000, #000 3px, transparent 3px, transparent 8px),
  linear-gradient(to right, #000, #000 3px, transparent 3px, transparent 8px),
  linear-gradient(to bottom, #000, #000 3px, transparent 3px, transparent 8px),
  linear-gradient(to bottom, #000, #000 3px, transparent 3px, transparent 8px);
  background-size: 8px 1px, 8px 1px, 1px 8px, 1px 8px;
  background-position: left top, left bottom, left top, right top;
  background-repeat: repeat-x, repeat-x, repeat-y, repeat-y;
  position: absolute;
  top: 0;
  bottom: 0;
  left: 0;
  right: 0;
  pointer-events: none;
}

/* example2 */
.example2::before {
  content: "";
  background-image: linear-gradient(to right, #000, #000 5px, transparent 5px, transparent 12px),
  linear-gradient(to right, #000, #000 5px, transparent 5px, transparent 12px),
  linear-gradient(to bottom, #000, #000 5px, transparent 5px, transparent 12px),
  linear-gradient(to bottom, #000, #000 5px, transparent 5px, transparent 12px);
  background-size: 12px 2px, 12px 2px, 2px 12px, 2px 12px;
  background-position: left top, left bottom, left top, right top;
  background-repeat: repeat-x, repeat-x, repeat-y, repeat-y;
  position: absolute;
  top: 0;
  bottom: 0;
  left: 0;
  right: 0;
  pointer-events: none;
}

/* example3 */
.example3::before {
  content: "";
  background-image: linear-gradient(to right, #000, #000 15px, transparent 15px, transparent 20px),
  linear-gradient(to right, #000, #000 15px, transparent 15px, transparent 20px),
  linear-gradient(to bottom, #000, #000 15px, transparent 15px, transparent 20px),
  linear-gradient(to bottom, #000, #000 15px, transparent 15px, transparent 20px);
  background-size: 20px 2px, 20px 2px, 2px 20px, 2px 20px;
  background-position: left top, left bottom, left top, right top;
  background-repeat: repeat-x, repeat-x, repeat-y, repeat-y;
  position: absolute;
  top: 0;
  bottom: 0;
  left: 0;
  right: 0;
  pointer-events: none;
}