text: var pupils;
  
  function tick () {
  
      var gamepad = navigator.getGamepads()[0];
  
      if (gamepad && pupils) {
          pupils.forEach(function (pupil, index) {
              index *= 2;
              var position = [
                  75 + (gamepad.axes[index] * 75),
                  75 + (gamepad.axes[index + 1] * 75)
              ];
              pupil.style.left = position[0] + 'px';
              pupil.style.top = position[1] + 'px';
          });
      }
  
      requestAnimationFrame(tick);
  }
  requestAnimationFrame(tick);
  
  window.onload = function () {
      pupils = document.querySelectorAll('.pupil');
  };