 {
      width: 100px;
      height: 100px;
      flex: none;
      background-color: green;
  }
  .spacer {
      flex: none;
      height: 100px;
      width: 100px;
  }

</style>
<div class="spacer"></div>
<div class="container">
  <div class="spacer"></div>
  <div class="parent"></div>
<div class="spacer"></div>
<div class="container">
  <div class="spacer"></div>
  <div class="parent_overflow"></div>
</body>
