// Start slow opening on bubbles
        var interval;
        d3.select('body').on('keydown', function() {
          if(d3.event.which === 32) {
            if (interval) {
              clearInterval(interval);
              interval = null;
            } else {
              interval = setInterval(function() {
                var expandable = vis.selectAll("circle")
                  .filter(function() { return d3.select(window.ppp = this).on('mouseover'); })[0];

                if (expandable.length > 0) {
                  var ex = expandable[Math.floor(Math.random() * expandable.length)];
                  d3.select(ex).on('mouseover');
                } else {
                  clearInterval(interval);
                  interval = null;
                }
              }, 150);
            }
          }
        });