css/css-overflow/column-scroll-marker-002-ref.html

<!DOCTYPE html>
<link rel="author" title="Morten Stenshorne" href="mailto:mstensho@chromium.org">
<style>
  #fakegroup > div {
    float: left;
    display: flex;
    justify-content: center;
    align-items: center;
    width: 50px;
    height: 50px;
  }
  .fakecolumn {
    float: left;
    width: 140px;
    height: 100px;
    background: yellow;
  }

</style>
<div style="width:450px; line-height:20px;">
  <div id="fakegroup">
    <div style="background:hotpink;"><a href="#">*</a></div>
    <div style="background:cyan;"></div>
    <div style="background:hotpink;"><a href="#">*</a></div>
    <div style="background:cyan;"></div>
    <div style="background:hotpink;"><a href="#">*</a></div>
    <div style="background:cyan;"></div>
    <div style="background:hotpink;"><a href="#">*</a></div>
    <div style="background:cyan;"></div>
    <div style="background:hotpink;"><a href="#">*</a></div>
  </div>
  <div style="display:flow-root; border:15px solid;">
    <div class="fakecolumn">Second column</div>
    <div class="fakecolumn">Third column</div>
    <div class="fakecolumn">Fourth column</div>
  </div>
</div>