<div class="parent">
  <div class="gear">
    <div class="center"></div>
    <div class="tooth"></div>
    <div class="tooth"></div>
    <div class="tooth"></div>
    <div class="tooth"></div>
  </div>  
</div>

body{background: #198;}

.parent{
  display: flex;
  height: 500px;
}

.gear{
  position: relative;
  width: 200px;
  height: 200px;
  margin: auto;
  background: #fff;
  border-radius: 50%;
  animation-name: spin;
  animation-duration: 4s;
  animation-iteration-count: infinite;
  animation-timing-function: linear;
}

.gear .center{
  position: absolute;
  top: 50px;
  left: 50px;
  z-index: 10;
  width: 100px;
  height: 100px;
  background: #198;
  border-radius: 50%;
}

.tooth{
  position: absolute;
  top: -25px;
  left: 75px;
  z-index: 1;
  width: 45px;
  height: 250px;
  background:#fff;
}

.tooth:nth-child(2){
  transform: rotate(45deg);
}

.tooth:nth-child(3){
  transform: rotate(90deg);
}

.tooth:nth-child(4){
  transform: rotate(135deg);
}

@keyframes spin {
  from {transform: rotate(0deg); }
  to {transform: rotate(360deg);}
}