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

html,body {
  display: grid;
  justify-items: center;
  align-content: center;
  
  width: 100%;
  height: 100%;
  background-color: #eaeaea;
}

.box {
  width: 100px;
  height: 100px;
  background-color: indianred;
}

.swing {
  animation-name: swing;
  animation-duration: 2s;
  animation-delay: 2s;
  animation-iteration-count: infinite;
  animation-direction: alternate;
  animation-fill-mode: backwards;
}

@keyframes swing {
  /* These styles will be applied throughout the animation */
  0%, 100% { 
    border-radius: 50%; 
    transform-origin: 0 -100px; 
  }
  
  0% { 
    transform: rotate(77deg); 
  }
  
  100% { 
    transform: rotate(-45deg);
  }
}