#loading {
  position: relative;
  text-align: center;
  margin: auto;
  width: 100px;
  height: 300px;
  align-content: center;
}

#loading > span {
  height: 300px;
  display: inline-flex;
}

@keyframes loading {
  0% {
    height: 1px;
  }
  100% {
    height: 100%;
  }
}

.pip {
  margin: 0 2px;
  align-self: flex-end;
  width: 10px;
  height: 1px;
  background-color: red;
  animation: loading 5s ease alternate infinite;
}

.pip:nth-of-type(even) {
  animation-delay: 0.5s;
  animation-duration: 3s;
}

.pip:last-of-type {
  animation-delay: 1s;
  animation-duration: 4s;
}