How to reverse a sequence of CSS transitions and t

This CSS "animation" in essence consist of several transitions and transforms on span:nth-children which follow each other sequentially using transition delays. It works fine one way, but what is the best way to reverse the animation? Since it is a sequence the solution should reverse the entire sequence. See fiddle for example: http://jsfiddle.net/musicformellons/6nb0wy68/

#Pqb-icon {
  background: white;
  width: 170px;
  height: 100px;
  border-radius: 5px;  
  position: relative;
  overflow: hidden;
  border: 2px solid salmon;
  border-bottom: 20;
  -webkit-transition: .9s ease-in-out;
  -moz-transition: .9s ease-in-out;
  -o-transition: .9s ease-in-out;
  transition: .9s ease-in-out;
}

#Pqb-icon span {
  display: block;
  position: absolute;
  border: 5px solid black;
  width: 20px;
  height: 20px;
  bottom: 50px;
  left: 12%;
  background: rgba(255, 200, 220, 0.4);
  transition-timing-function: ease;
}

#Pqb-icon span:nth-child(1) {
  left: 12%;
  border-radius: 25px;
  -webkit-transform-origin: left center;
  -moz-transform-origin: left center;
  -o-transform-origin: left center;
  transform-origin: left center;
}

#Pqb-icon.open span:nth-child(1) {
  left: 12%;
  border-radius: 25px;
  -webkit-transition: .25s ease-in-out;
  -moz-transition: .25s ease-in-out;
  -o-transition: .25s ease-in-out;
  transition: .25s ease-in-out;
}

#Pqb-icon.open span:nth-child(3) {
  left: 36%;
  bottom: 50px;
  border-radius: 25px;
  -webkit-transform: translate(-40px,0px);
  -moz-transform: translate(-40px,0px);
  -o-transform: translate(-40px,0px);
  transform: translate(-40px,0px);
  -webkit-transition: .25s ease .7s;
  -moz-transition: .25s ease .7s;
  -o-transition: .25s ease .7s;
  transition: .4s ease .9s;
  opacity: 0;
}

#Pqb-icon span:nth-child(2) {
  width: 5px;    
  height: 38%;
  bottom: 27%;
  background: black;
  border: 0px solid black;
  -webkit-transform-origin: left center;
  -moz-transform-origin: left center;
  -o-transform-origin: left center;
  transform-origin: left center;
}

#Pqb-icon.open span:nth-child(2) {
  width: 5px;    
  height: 38%;
  bottom: 27%;
  background: black;
  border: 0px solid black;
  -webkit-transition: .25s ease-in-out;
  -moz-transition: .25s ease-in-out;
  -o-transition: .25s ease-in-out;
  transition: .25s ease;
}

#Pqb-icon.open span:nth-child(4) {
  width: 5px;    
  height: 38%;
  bottom: 27%;
  left: 15%;
  background: black;
  border: 0px solid black;
  -webkit-transform: rotateZ(-180deg);
  -moz-transform: rotateZ(-180deg);
  -o-transform: rotateZ(-180deg);
  transform: rotate(-180deg) ;
  -webkit-transition: .25s ease-in-out .7s;
  -moz-transition: .25s ease-in-out .7s;
  -o-transition: .25s ease-in-out .65s;
  transition: .4s ease .8s;
  opacity: 0;
}

#Pqb-icon span:nth-child(3) {
  bottom: 27%;
  left: 28.5%;
  border-radius: 25px;
  -webkit-transform-origin: left center;
  -moz-transform-origin: left center;
  -o-transform-origin: left center;
  transform-origin: left center;
}

#Pqb-icon.open span:nth-child(5) {
  bottom: 27%;
  left: 46%;
  border-radius: 25px;
  -webkit-transform: rotateZ(-180deg);
  -moz-transform: rotateZ(-180deg);
  -o-transform: rotateZ(-180deg);
  transform: rotateZ(-180deg) ;
  -webkit-transition: .35s ease-in-out;
  -moz-transition: .35s ease-in-out;
  -o-transition: .35s ease-in-out;
  transition: .4s ease .4s;
  opacity: 0;
}

#Pqb-icon span:nth-child(4) {
  width: 5px; 
  height: 32%;
  bottom: 10%;
  left: 43%;
  background: black;
  border: 0px solid black;
  -webkit-transform-origin: left center;
  -moz-transform-origin: left center;
  -o-transform-origin: left center;
  transform-origin: left center;
}

#Pqb-icon.open span:nth-child(6) {
  width: 5px; 
  height: 32%;
  bottom: 10%;
  left: 46.5%;
  background: black;
  border: 0px solid black;
  -webkit-transform: rotateZ(-180deg);
  -moz-transform: rotateZ(-180dreg);
  -o-transform: rotateZ(-180deg);
  transform: rotateZ(-180deg) ;
  -webkit-transition: .35s ease-in-out .35s;
  -moz-transition: .35s ease-in-out .35s;
  -o-transition: .35s ease-in-out .35s;
  transition: .4s ease .4s;
  opacity: 0;
}

#Pqb-icon span:nth-child(5) {
  bottom: 27%;
  left: 51%;
  border-radius: 25px;
  -webkit-transform-origin: left center;
  -moz-transform-origin: left center;
  -o-transform-origin: left center;
  transform-origin: left center;
}

#Pqb-icon span:nth-child(6) {
  width: 5px; 
  height: 35%;
  bottom: 40%;
  left: 51%;
  background: black;
  border: 0px solid black;
  -webkit-transform-origin: left center;
  -moz-transform-origin: left center;
  -o-transform-origin: left center;
  transform-origin: left center;
}

Since you are only using transition and already have the toggleClass method, you don't need to change anything in the JS to reverse the transition effect. All that you need to do is add a different transition setting to the default state (not with class='open') like the below snippet.

Essentially what we are doing is this:

The elements that are causing the effect are the third, fourth, fifth and sixth span elements.
Initially for the move out effect, the fifth and sixth span elements move out with a delay of .4s.
The third and fourth span elements move out with a delay of 0.8s (or 0.9s). This has an extra delay because it has to move out after the fifth and sixth are out of the way. The fifth and sixth spans will take 0.4s (transition duration) + 0.4s (transition delay) = 0.8s to complete.
On toggling the class off, we need this to happen in reverse. That is, the third and fourth span elements should move in to view at a delay of 0.4s while the fifth and sixth span should move in after a delay of 0.8s. So adding the appropriate transition settings to the following selectors would be enough:
- #Pqb-icon span:nth-child(3) {transition: .4s ease .4s;}
- #Pqb-icon span:nth-child(4) {transition: .4s ease .4s;}
- #Pqb-icon span:nth-child(5) {transition: .4s ease .9s;}
- #Pqb-icon span:nth-child(6) {transition: .4s ease .9s;}

Note: I have removed the vendor prefixes in the snippet and added the prefix library to keep the code small.

$('#Pqb-icon').on('click', function() {
    $(this).toggleClass('open');
  });

#Pqb-icon {
  background: white;
  width: 170px;
  height: 100px;
  border-radius: 5px;  /*dikte van rondjes*/
  position: relative;
  overflow: hidden;
  border: 2px solid salmon;
  border-bottom: 20;
  transition: .9s ease-in-out;
}
#Pqb-icon span {
  display: block;
  position: absolute;
  border: 5px solid black;
  width: 20px;
  height: 20px;
  bottom: 50px;
  left: 12%;
  background: rgba(255, 200, 220, 0.4);
  transition-timing-function: ease;
}

/* BEFORE collapsed: hamburger */

#Pqb-icon span:nth-child(1) {
  left: 12%;
  border-radius: 25px;
  transition: .25s ease-in-out;
  transform-origin: left center;
}
#Pqb-icon.open span:nth-child(1) {
  left: 12%;
  border-radius: 25px;
}
#Pqb-icon span:nth-child(2) {
  width: 5px;
  height: 38%;
  bottom: 27%;
  background: black;
  border: 0px solid black;
  transition: .25s ease;
  transform-origin: left center;
}
#Pqb-icon.open span:nth-child(2) {
  width: 5px;
  height: 38%;
  bottom: 27%;
  background: black;
  border: 0px solid black;
}
#Pqb-icon span:nth-child(3) {
  bottom: 27%;
  left: 28.5%;
  border-radius: 25px;
  transition: .4s ease .4s;
  transform-origin: left center;
}
#Pqb-icon.open span:nth-child(3) {
  left: 36%;
  bottom: 50px;
  border-radius: 25px;
  transition: .4s ease .9s;
  transform: translate(-40px, 0px);
  opacity: 0;
}
#Pqb-icon span:nth-child(4) {
  width: 5px;
  height: 32%;
  bottom: 10%;
  left: 43%;
  background: black;
  border: 0px solid black;
  transition: .4s ease .4s;
  transform-origin: left center;
}
#Pqb-icon.open span:nth-child(4) {
  width: 5px;
  height: 38%;
  bottom: 27%;
  left: 15%;
  background: black;
  border: 0px solid black;
  transition: .4s ease .9s;
  transform: rotate(-180deg);
  opacity: 0;
}
#Pqb-icon span:nth-child(5) {
  bottom: 27%;
  left: 51%;
  border-radius: 25px;
  transition: .4s ease .9s;
  transform-origin: left center;
}
#Pqb-icon.open span:nth-child(5) {
  bottom: 27%;
  left: 46%;
  border-radius: 25px;
  transition: .4s ease .4s;
  transform: rotateZ(-180deg);
  opacity: 0;
}
#Pqb-icon span:nth-child(6) {
  width: 5px;
  height: 35%;
  bottom: 40%;
  left: 51%;
  background: black;
  border: 0px solid black;
  transition: .4s ease .9s;
  transform-origin: left center;
}
#Pqb-icon.open span:nth-child(6) {
  width: 5px;
  height: 32%;
  bottom: 10%;
  left: 46.5%;
  background: black;
  border: 0px solid black;
  transition: .4s ease .4s;
  transform: rotateZ(-180deg);
  opacity: 0;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/prefixfree/1.0.7/prefixfree.min.js"></script>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.0/jquery.min.js"></script>
<button type="button">
  <span class="sr-only">Toggle navigation</span>
  <div id="Pqb-icon">
    <span class="icon-bar"></span>
    <span class="icon-bar"></span>
    <span class="icon-bar"></span>
    <span class="icon-bar"></span>
    <span class="icon-bar"></span>
    <span class="icon-bar"></span>
  </div>
</button>