<div class="container">
  <div class="line">
    <span></span>
    <span></span>
    <span></span>
    <span></span>
    <span></span>
  </div>
</div>

body {
  margin: 0;
}

.container {
  background-color: #ccc;
}

.line {
  background: linear-gradient(45deg, #12B55D -33.12%, #CAE700 49.77%, #FFF113 70.01%, #FFC522 92.17%, #FF7122 118.83%);
  width: 40px;
  margin-left: 100px;
  overflow: hidden;
}

.line span {
  display: block;
  margin-bottom: 30px;
  padding-bottom: 100%;
  border-radius: 15px;
  box-shadow: 0 0 0 30px #ccc;
}

.line span:last-child {
  margin-bottom: 0;
}