Как сделать неровный блок с помощью css?

:root {
  --pin-height: 30px;
  --pin-inline-offset:12px;
}

li {
  list-style: none;
}

.boxWrapper {
  display: inline-block;
  padding-top: var(--pin-height);
  position: relative;
  width: 250px;
}

.boxWrapper::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  background-color: grey;
  width: 250px;
  height: var(--pin-height);
  clip-path: polygon(50% 0%, var(--pin-inline-offset) 100%, calc(100% - var(--pin-inline-offset)) 100%);
}

.box {
  background-color: grey;
  border-radius: 15px;
  padding-inline :20px;
}

.item {
  text-align: center;
}

.item + .item {
  border-top: 1px solid white;
}

    <div class="boxWrapper">
  <div class="box">
    <li class="item">1</li>
    <li class="item">2</li>
    <li class="item">3</li>
    <li class="item">4</li>
    <li class="item">5</li>
    <li class="item">6</li>
    <li class="item">7</li>
    <li class="item">8</li>
    <li class="item">9</li>
    <li class="item">10</li>  
  </div>
</div>