title: Flexbox: 3 divs, 2 columns
body: <p>I'm new to flexbox, so please bear with me. My html:</p>
  
  <pre><code>&lt;div class="container"&gt;
      &lt;div class="one"&gt;&lt;/div&gt;
      &lt;div class="two"&gt;&lt;/div&gt;
      &lt;div class="three"&gt;&lt;/div&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>With flexbox, I am trying to achieve the following layout:</p>
  
  <p><img src="https://i.stack.imgur.com/dwlRk.png" alt="the following layout">.</p>
  
  <p>What's the simplest way I can achieve this <strong>without setting a height for the container?</strong> .one is expected to change in height.</p>