@-webkit-keyframes rotating {
    from{
        -webkit-transform: rotate(0deg);
    }
    to{
        -webkit-transform: rotate(360deg);
  }
}
.b {
  -webkit-animation: rotating 2.5s linear infinite;
  transform-origin: 50% 50%;
  border-left: 2px solid #2ecc71; 
  height: 40px;
  width: 40px;
  border-radius: 50%;
  margin: 0 auto;
  margin-top: 150px;
  padding: 10px;
}
.c {
  -webkit-animation: rotating 2.5s linear infinite;
  transform-origin: 50% 50%;
  border-left: 2px solid #3498db; 
  height: 30px;
  width: 30px;
  border-radius: 50%;
  margin-top: 5px;
  margin-bottom: 5px;
}
.d {
  -webkit-animation: rotating 2.5s linear infinite;
  transform-origin: 50% 50%;
  border-left: 2px solid #9b59b6; 
  height: 20px;
  width: 20px;
  border-radius: 50%;
  margin-top: 5px;
  margin-bottom: 5px;
  float: right;
}