SOURCE

<div class="div1">

  <div class="flex_box">
  <div class="item"></div>

   <div class="item"></div>

  <div class="item"></div> 
</div>
  <div class="div2"></div>

</div>

.div1{
  position:relative;
  border:1px solid red;
}
.flex_box{
  border:1px solid red;
  width:80%;
  display:flex;
  justify-content:space-between;
  align-items:center;

}
.item{
  width:20px;
  height:70px;
  border:1px solid blue;
}
.line,.line2{
  border:1px solid green;
  flex:1;
  height:0px;
}
.line2{
  border:1px solid blue;
}
.div2{
  position:absolute;
  top:10px;
  
  
}