SOURCE

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

.box{
  position: relative;
  margin: 0 auto;
  width: 300px;
  height: 300px;
  border-bottom: 10px solid black;
  border-radius: 50%;
  transform: rotateZ(30deg);
  &::before, &::after{
    content: ' ';
    position: absolute;
    width: 30px;
    height: 30px;
    border-radius: 50%;
    background: black;
    top: 30%;
  }
  &::before{
    left: 20%;
  }
  &::after{
    right: 20%;
  }
}