<div class='container'>
    <button>1</button>
    <button>2</button>
    <button>3</button>
    <button class="item-4">4</button>
    <button class="item-5">5</button>
    <button>6</button>
  </div>
.container {
  display: grid;
  grid-template-columns: 80px 80px 80px 80px;
  grid-template-rows: 30px 30px;
  grid-auto-flow: row;
}

.item-4 {
  grid-column: 4;
  grid-row: 1 / 3;
}

.item-5 {
  grid-column:  1 / 3;
}

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External JavaScript

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