box {
    display: inline-block;
    width: 60px;
    background-color: blue;
  }
  </style>

  <main class="container">
    <div class="shape"></div>
    <div class="box" style="height: 12px;"></div> <!-- Box at corner -->
    <div class="box" style="height: 12px;"></div> <!-- Box at corner -->
    <div class="box" style="height: 36px;"></div>
    <div class="box" style="height: 36px;"></div>
    <div class="box" style="height: 12px;"></div> <!-- Box at corner -->
    <div class="box" style="height: 12px;"