public function next($eye = '-')
    {
        if (!isset($this->states[++$this->index])) {
            $this->index = 0;
        }

        $state = $this->states[$this->index];

        foreach ($state as &$line) {
            $line = str_pad(
                str_replace('%', $eye, $line),
                $this->getWidth()
            );
        }

        return $state;
    }