title: how to make contents flow vertically
body: <p>I am creating a dynamic site where there is a parent div and children divs (they are variable in width) inside the parent one and trying to make this :
  when a new div is created it is pushed downward until it the parents height is filled then start a new column and such as:</p>
  
  <p>IMAGE:</p>
  
  <p><a href="https://i.stack.imgur.com/gkaZZ.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/gkaZZ.png" alt="enter image description here"></a></p>
  
  <pre><code> &lt;style&gt;
      .parent {
        height: 800px;
        width: 100%;
        overflow-y: hidden;
        border: 1px solid black;
      }
      .child1 {
        background-color: blue;
        height: 150px;
        width: 150px;
      }
      .child1 {
        background-color: red;
        height: 150px;
        width: 300px;
      }
      &lt;/style&gt;
  
      &lt;div class="parent"&gt;
        &lt;div class="child1"&gt;&lt;/div&gt;
        &lt;div class="child1"&gt;&lt;/div&gt;
        &lt;div class="child1"&gt;&lt;/div&gt;
        &lt;div class="child2"&gt;&lt;/div&gt;
        &lt;div class="child1"&gt;&lt;/div&gt;
        &lt;div class="child1"&gt;&lt;/div&gt;
        &lt;div class="child2"&gt;&lt;/div&gt;
        &lt;div class="child1"&gt;&lt;/div&gt;
        &lt;div class="child1"&gt;&lt;/div&gt;
        &lt;div class="child1"&gt;&lt;/div&gt;
        &lt;div class="child2"&gt;&lt;/div&gt;
        &lt;div class="child1"&gt;&lt;/div&gt;
        &lt;div class="child1"&gt;&lt;/div&gt;
        &lt;div class="child2"&gt;&lt;/div&gt;
      &lt;/div&gt;
  </code></pre>