y: flex;
  }
</style>
<div class="corner"></div>
<div class="vertical-edge">
  <div style="width:5.25em; height:10em; background:hotpink;">
    x x x x x
  </div>
  <div style="width:9.5em; margin-top:1em; height:10em; background:cyan;">
    x x x x x x x x x
  </div>
  <div style="width:5.25em; margin-top:2em; height:10em; background:yellow;">
    x x
  </div>
</div>
<div class="corner"></div>
<div class="horizontal-edge"></div>
<div></div>
<div></div>
<div class="corner"></div>
<div class="vertical-edge">