<div class="grid">
  <div class="item">1</div>
  <div class="item">2</div>
  <div class="item">3</div>
  <div class="item">4</div>
  <div class="item">5</div>
  <div class="item">6</div>
  <div class="item">7</div>
  <div class="item">8</div>
</div>

.grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 5px;
}
.item:nth-child(4n + 1),
.item:nth-child(4n) {
  grid-column: span 2;
}


/* Эти стили только для оформления */
body {
  background: #eee;
}
.item {
  background: white;
  border: 2px solid;
  text-align: center;
  font-size: 20px;
  font-weight: bold;
  font-family: sans-serif;
  padding: 1rem;
  box-sizing: border-box;
}