HTML:



<div></div>

<div></div>

<div></div>

<div></div>

<div></div>

<div></div>

<div></div>

<div></div>

<div></div>

<div></div>

<div></div>



CSS:



div {

  border-radius:50%;

  position:absolute;

  top:50%; left:75%;

}

div:nth-of-type(odd) { background:black; }

div:nth-of-type(even) { background:white; border:2px solid black; }

div:nth-of-type(11) {

  height:10px; width:10px;

  margin-top:-5px; margin-left:-5px;

  -webkit-animation:slide 3s ease-in-out infinite;

  animation:slide 3s ease-in-out infinite;

}

div:nth-of-type(10) {

  height:20px; width:20px;

  margin-top:-12px; margin-left:-12px;

  -webkit-animation:slide 3s -2.7s ease-in-out infinite;

  animation:slide 3s -2.7s ease-in-out infinite;

}

div:nth-of-type(9) {

  height:40px; width:40px;

  margin-top:-20px; margin-left:-20px;

  -webkit-animation:slide 3s -2.4s ease-in-out infinite;

  animation:slide 3s -2.4s ease-in-out infinite;

}

div:nth-of-type(8) {

  height:60px; width:60px;

  margin-top:-32px; margin-left:-32px;

  -webkit-animation:slide 3s -2.1s ease-in-out infinite;

  animation:slide 3s -2.1s ease-in-out infinite;

}

div:nth-of-type(7) {

  height:80px; width:80px;

  margin-top:-40px; margin-left:-40px;

  -webkit-animation:slide 3s -1.8s ease-in-out infinite;

  animation:slide 3s -1.8s ease-in-out infinite;

}

div:nth-of-type(6) {

  height:100px; width:100px;

  margin-top:-52px; margin-left:-52px;

  -webkit-animation:slide 3s -1.5s ease-in-out infinite;

  animation:slide 3s -1.5s ease-in-out infinite;

}

div:nth-of-type(5) {

  height:120px; width:120px;

  margin-top:-60px; margin-left:-60px;

  -webkit-animation:slide 3s -1.2s ease-in-out infinite;

  animation:slide 3s -1.2s ease-in-out infinite;

}

div:nth-of-type(4) {

  height:140px; width:140px;

  margin-top:-72px; margin-left:-72px;

  -webkit-animation:slide 3s -0.9s ease-in-out infinite;

  animation:slide 3s -0.9s ease-in-out infinite;

}

div:nth-of-type(3) {

  height:160px; width:160px;

  margin-top:-80px; margin-left:-80px;

  -webkit-animation:slide 3s -0.6s ease-in-out infinite;

  animation:slide 3s -0.6s ease-in-out infinite;

}

div:nth-of-type(2) {

  height:180px; width:180px;

  margin-top:-92px; margin-left:-92px;

  -webkit-animation:slide 3s -0.3s ease-in-out infinite;

  animation:slide 3s -0.3s ease-in-out infinite;

}

div:nth-of-type(1) {

  height:200px; width:200px;

  margin-top:-100px; margin-left:-100px;

  -webkit-animation:slide 3s ease-in-out infinite;

  animation:slide 3s ease-in-out infinite;

}

@keyframes slide {

  0% { left:75% }

  50% { left:25%; }

  100% { left:75%; }

}

@-webkit-keyframes slide {

  0% { left:75% }

  50% { left:25%; }

  100% { left:75%; }

}