*{
  box-sizing:border-box;
  margin:0;
  padding:0;
}
html,
body {
  height:100vh;
  display:flex;
  align-items:center;
  justify-content:center;
  background-color: #e8e8e8;
  font-family:arial;
}
.loader {
  scale: 3;
  height: 50px;
  width: 40px;
}

.box {
  position: relative;
  opacity: 0;
  left: 10px;
}

.side-left {
  position: absolute;
  background-color: #286cb5;
  width: 19px;
  height: 5px;
  transform: skew(0deg, -25deg);
  top: 14px;
  left: 10px;
}

.side-right {
  position: absolute;
  background-color: #2f85e0;
  width: 19px;
  height: 5px;
  transform: skew(0deg, 25deg);
  top: 14px;
  left: -9px;
}

.side-top {
  position: absolute;
  background-color: #5fa8f5;
  width: 20px;
  height: 20px;
  rotate: 45deg;
  transform: skew(-20deg, -20deg);
}

.box-1 {
  animation: from-left 4s infinite;
}

.box-2 {
  animation: from-right 4s infinite;
  animation-delay: 1s;
}

.box-3 {
  animation: from-left 4s infinite;
  animation-delay: 2s;
}

.box-4 {
  animation: from-right 4s infinite;
  animation-delay: 3s;
}

@keyframes from-left {
  0% {
    z-index: 20;
    opacity: 0;
    translate: -20px -6px;
  }

  20% {
    z-index: 10;
    opacity: 1;
    translate: 0px 0px;
  }

  40% {
    z-index: 9;
    translate: 0px 4px;
  }

  60% {
    z-index: 8;
    translate: 0px 8px;
  }

  80% {
    z-index: 7;
    opacity: 1;
    translate: 0px 12px;
  }

  100% {
    z-index: 5;
    translate: 0px 30px;
    opacity: 0;
  }
}

@keyframes from-right {
  0% {
    z-index: 20;
    opacity: 0;
    translate: 20px -6px;
  }

  20% {
    z-index: 10;
    opacity: 1;
    translate: 0px 0px;
  }

  40% {
    z-index: 9;
    translate: 0px 4px;
  }

  60% {
    z-index: 8;
    translate: 0px 8px;
  }

  80% {
    z-index: 7;
    opacity: 1;
    translate: 0px 12px;
  }

  100% {
    z-index: 5;
    translate: 0px 30px;
    opacity: 0;
  }
}