public function slider($adjacent = 3)
        {
            $window = $adjacent * 2;

            // If the current page is so close to the beginning that we do not have
            // room to create a full sliding window, we will only show the first
            // several pages, followed by the ending of the slider.
            //
            // Likewise, if the page is very close to the end, we will create the
            // beginning of the slider, but just show the last several pages at
            // the end of the slider. Otherwise, we'll build the range.
            //
            // Example: 1 [2] 3 4 5 6 ... 23 24
            if ($this->page <= $window)  {
                return $this->range(1, $window + 2).' '.$this->ending();
            } elseif ($this->page >= $this->last - $window) {
                return $this->beginning().' '.$this->range($this->last - $window - 2, $this->last);
            }

            // Example: 1 2 ... 23 24 25 [26] 27 28 29 ... 51 52
            $content = $this->range($this->page - $adjacent, $this->page + $adjacent);

            return $this->beginning() . ' ' . $content . ' ' . $this->ending();
        }