public function generateLinesDiagonally()
    {
        $return = [];
        $max = $this->matrix->rows;
        if ($max < $this->matrix->columns) {
            $max = $this->matrix->columns;
        }

        $tmp1 = [];
        $index = $this->firstColumn[0];
        for ($i = 0; $i < $max; $i++) {
            if ($i < $this->matrix->rows) {
                $index = $i * ($this->matrix->rows + 1);
            } else {
                $index = $index + $this->matrix->rows - 1;
            }
            $tmp1[] = $index;
        }

        $tmp2 = [];
        $index = end($this->firstColumn);
        for ($i = 1; $i < $max+1; $i++) {
            if ($i <= $this->matrix->rows) {
                $index = $i * ($this->matrix->rows - 1);
            } else {
                $index = $index + ($this->matrix->rows + 1);
            }
            $tmp2[] = $index;
        }

        $return[] = $tmp1;
        $return[] = $tmp2;

        var_dump($return);
    }