JSFiddle - React, Tailwind, and code Playground

JavaScript

var log = function (msg) {
    var p = document.createElement('p');
    p.innerHTML = msg;
    document.getElementsByTagName('body')[0].appendChild(p);
},
test = function () {
    var maxElements = 36,
        i = 0,
        html;
    for (i = 0; i < (maxElements * 5); i += 1) {
        log('incrementing index: ' + (i % maxElements).toString() + ' and decrementing index: ' + ((maxElements - 1) - (i % maxElements)).toString());
    }
};
test();