JSFiddle - React, Tailwind, and code Playground

HTML

<div class="col">
  <div class="block block1"></div>
  <div class="block block2"></div>
  <div class="block block3"></div>
</div>

CSS

.col{
  display: flex;
  flex-direction: column;
  flex-wrap: wrap;
  height: 150px;
}

.block{
  width: 100px;
  flex-basis: 50px;
  border: 1px solid #f90;
  background-color: #777;
}

.block1{
  flex-basis: 100%;
}