protected function exitHorizontalFrames(array $lines, $line_method)
    {
        $keyframes = [];
        $length    = mb_strlen($lines[0]);

        for ($i = $length; $i > 0; $i--) {
            $keyframes[] = $this->getHorizontalKeyframe($lines, $i, $line_method, $length);
        }

        return $keyframes;
    }