Edit in JSFiddle

<p><strong>normal</strong>: 0% --&gt; 100%</p>
<div class="normal">
  <div></div>
</div>
<p><strong>reverse</strong>: 100% --&gt; 0%</p>
<div class="reverse">
  <div></div>
</div>
<p><strong>alternate</strong>: 0% &lt;--&gt; 100%</p>
<div class="alternate">
  <div></div>
</div>
<p><strong>alternate-reverse</strong>: 100% &lt;--&gt; 0%</p>
<div class="alternate-reverse">
  <div></div>
</div>

p{ color: grey;}
.normal div{ animation-direction: normal;}
.reverse div{ animation-direction: reverse;}
.alternate div{ animation-direction: alternate;}
.alternate-reverse div{ animation-direction: alternate-reverse;}
p:nth-child(1) strong{ color: crimson;}
div:nth-child(2) div{ background: crimson;}
p:nth-child(3) strong{ color: midnightblue;}
div:nth-child(4) div{ background: midnightblue;}
p:nth-child(5) strong{ color: mediumseagreen;}
div:nth-child(6) div{ background: mediumseagreen;}
p:nth-child(7) strong{ color: goldenrod;}
div:nth-child(8) div{ background: goldenrod;}
div {
    background: white;
    height: 20px;
    width: 220px;
}
div div {
    animation: swipe 2s linear infinite;
    background: crimson;
    height: 20px;
    left: 0;
    margin-top: -1rem;
    position: relative;
    transition: 1s;
    width: 20px;
}
@keyframes swipe {
  0%  { left: 0;}
  100%{ left: 200px;}
}