@keyframes anim {
  
  0% {
    left: 0px;
    top: 0px;
  }
  
  25% {
    left: 100px;
    top: 0px;
  }
    
  50% {
    left: 100px;
    top: 100px;
  }
  
  75% {
    left: 0px;
    top: 100px;
  }
  
  100% {
    left: 0px;
    top: 0px;
  }
  
}

#box {
  position: absolute;
  border: 1px solid black;
	animation: anim 5s linear infinite;
}