<ul>
  <li class="v-shape">Item 1</li>
  <li>Item 2</li>
  <li>Item 3</li>
</ul>

.v-shape::before,
.v-shape::after {
  content: "";
  position: absolute;
  top: 0;
  width: 0;
  height: 0;
  border-style: solid;
  border-width: 0 5px 10px 5px;
  border-color: transparent transparent #000 transparent;
}

.v-shape::before {
  left: -5px;
  transform: rotate(45deg);
}

.v-shape::after {
  right: -5px;
  transform: rotate(-45deg);
}

.v-shape {
  position: relative;
}