<div class="box"></div><div class="box"></div>

body {
  height: 100vh;
  background-image: linear-gradient(to top, skyblue, pink);
  position: relative;
  overflow: hidden;
} 

.box {
  width: 50px;
  height: 50px;
  position: absolute;
  top: 50%;
  left: 0;
  right: 0;
  bottom: 0;
  margin: 0 auto;
}
.box::before {
  content: '';
  width: 50px;
  height: 5px;
  position: absolute;
  top: 58px;
  left: 0;
  background-color: #000;
  border-radius: 50%;
  opacity: 0.2;
  animation: shadow 0.6s linear infinite;
}
@keyframes shadow {
  0% { transform: scale(1, 1);}
  50% { transform: scale(1.2,1);}
  100% { transform: scale(1, 1);}
}

.box::after {
  content: '';
  background-color: yellow;
  width: 50px;
  height: 50px;
  position: absolute;
  top: 0;
  left: 0;
  border-radius: 3px;
  animation: load 0.6s linear infinite;
}

@keyframes load {
  17% { border-bottom-right-radius: 3px; }
  25% { transform: translatey(9px) rotate(22.5deg);}
  50% { 
    transform: translatey(18px) scale(1, 0.9) rotate(45deg);
    border-bottom-right-radius: 40px;
  }
  75% { transform: translatey(9px) rotate(97.5deg);}
  100% { transform: translatey(0px) rotate(90deg);}
}