<div id="anime-demo">
  <div class="line">
    <div class="square"></div>
    <div class="square"></div>
    <div class="square"></div>
    <div class="square"></div>
    <div class="square"></div>
  </div>
</div>
<div class="controls">
<button class="play-normal">Normal Animation</button>
<button class="play-reverse">Reverse Animation</button>
<button class="play-alternate">Alternating Animation</button>
</div>

body {
  margin: 20px;
  font-family: 'Lato';
  font-weight: 300;
  font-size: 1.2em;
  text-align: center;
}

button {
  background: orange;
  color: white;
  margin: 5px;
  padding: 10px;
  border-radius: 4px;
  font-family: 'Lato';
  cursor: pointer;
  border: none;
  outline: none;
}

button:hover {
  background: blue;
}

.square {
  pointer-events: none;
  position: relative;
  width: 80px;
  height: 80px;
  background-color: black;
  margin: 16px;
  display: inline-block;
}

.controls {
  margin-top: 300px;
}

var normalLoop = anime({
  targets: '.square',
  translateY: 250,
  delay: function(target, index) {
    return index * 200;
  },
  loop: 4,
  easing: 'easeInSine',
  autoplay: false
});

var reverseLoop = anime({
  targets: '.square',
  translateY: 250,
  delay: function(target, index) {
    return index * 200;
  },
  loop: 4,
  easing: 'easeInSine',
  direction: 'reverse',
  autoplay: false
});

var alternateLoop = anime({
  targets: '.square',
  translateY: 250,
  delay: function(target, index) {
    return index * 200;
  },
  loop: 4,
  easing: 'easeInSine',
  direction: 'alternate',
  autoplay: false
});

document.querySelector('.play-normal').onclick = normalLoop.restart;
document.querySelector('.play-reverse').onclick = reverseLoop.restart;
document.querySelector('.play-alternate').onclick = alternateLoop.restart;