<div class="parent">
  <div class="fence">
         <div></div>
         <div></div>
         <div></div>
         <div></div>
         <div></div>
         <div></div>
         <div></div>
         <div></div>
         <div></div>
  </div>
    <div class="fence2">
         <div></div>
         <div></div>
         <div></div>
         <div></div>
         <div></div>
         <div></div>
         <div></div>
         <div></div>
         <div></div>
  </div>
 </div>
.parent {
  display:flex;
  flex-direction: row
}
.fence, .fence2 { width: 50%; margin: 0;}

.fence2 {
  display:flex;
  flex-direction: column;
}
.fence2 div {
  margin-top: 10.25%;
  height: 8px;
  background: red;
}

.fence>div {
  position: absolute;
  /*top: 0;*/
  left: 0;
  right: 0;
  /*width: 100%;*/
  height: 0.55%;
  /*height: 2px;*/
  background: green;
}

.fence>div:nth-child(1) {
  top: 10%;
}

.fence>div:nth-child(2) {
  top: 20%;
}

.fence>div:nth-child(3) {
  top: 30%;
}

.fence>div:nth-child(4) {
  top: 40%;
}

.fence>div:nth-child(5) {
  top: 50%;
}

.fence>div:nth-child(6) {
  top: 60%;
}

.fence>div:nth-child(7) {
  top: 70%;
}

.fence>div:nth-child(8) {
  top: 80%;
}

.fence>div:nth-child(9) {
  top: 90%;
}
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