<div class="container">
  <div class="el" style="height:30px">1</div>
  <div class="el" style="height:40px">2</div>
  <div class="el" style="height:50px">3</div>
  <div class="el" style="height:60px">4</div>
  <div class="el" style="height:110px">5 </div>
  <div class="el" style="height:80px">6</div>
  <div class="el" style="height:90px">7</div>
  <div class="el" style="height:120px">8</div>
</div>

.container {
   display: flex;
   flex-wrap: wrap;
   flex-direction: column;
   height: 400px;
}

.el {
   background-color: gray;
   margin:4px;
}