JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://cdnjs.cloudflare.com/ajax/libs/jquery/1.9.0/jquery.min.js"></script>
<div id="content">
    <div id="up-left">
        <div id="box" class="brown">
            <h1>ONE</h1>
        </div>
        <div id="box" class="black">
            <h1>TWO</h1>
        </div>
        <div id="box" class="white">
            <h1>THREE</h1>
        </div>
        <div id="box" class="black">
            <h1>FOUR</h1>
        </div>
        <div id="box" class="white">
            <h1>FIVE</h1>
        </div>
        <div id="box" class="black">
            <h1>SIX</h1>
        </div>
    </div><!-- #up-left -->
    <div id="down-right">
        <div id="box" class="white">
            <h1>SIX</h1>
        </div>
        <div id="box" class="black">
            <h1>FIVE</h1>
        </div>
        <div id="box" class="white">
            <h1>FOUR</h1>
        </div>
        <div id="box" class="black">
            <h1>THREE</h1>
        </div>
        <div id="box" class="white">
            <h1>TWO</h1>
        </div>
        <div id="box" class="green">
            <h1>ONE</h1>
        </div>
    </div><!-- #down-right -->
</div><!-- .content -->

CSS

div#content {
    width: 100%;
    height: 100%;
    position: absolute;
    top:0;
    right:0;
    bottom:0;
    left:0;
}
#box {
    position: relative;
    vertical-align:top;
    width: 100%;
    height: 200px;
    margin: 0;
    padding: 0;
}
#up-left {
    position:absolute;
    z-index:4px;
    left: 0;
    top: 0px;
    width: 50%;
    margin: 0;
    padding: 0;
}
#down-right {
    position:fixed;
    bottom: 0px;
    z-index: 5px;
    left: 50%;
    width: 50%;
    margin: 0;
    padding: 0;
}
h1 {margin: 0;padding: 0;color:#fff}
.black {background: black;}
.white {background: grey;}
.green {background: green;}
.brown {background: brown;}

JavaScript

$(document).ready(function() {

    var num_children = $('#up-left').children().length;
    var child_height = $('#up-left').height() / num_children;
    var half_way = num_children * child_height / 2;
    $(window).scrollTop(half_way);

    function crisscross() {
        $('#up-left').css('bottom', '-' + window.scrollY + 'px');
        $('#down-right').css('bottom', '-' + window.scrollY + 'px');
        var firstLeft = $('#up-left').children().first();
        var lastLeft = $('#up-left').children().last();
        var lastRight = $('#down-right').children().last();
        var firstRight = $('#down-right').children().first();

        if (window.scrollY > half_way ) {

            $(window).scrollTop(half_way - child_height);
            lastRight.appendTo('#up-left');
            firstLeft.prependTo('#down-right');

        } else if (window.scrollY < half_way - child_height) {

            $(window).scrollTop(half_way);
            lastLeft.appendTo('#down-right');
            firstRight.prependTo('#up-left');
        }
    }
    
    $(window).scroll(crisscross);
 
});