In the interior, the same exuberant artistry can be admired in the sculpted wood organ frame and the stone tracery of the spiral staircase.
The spiral staircase is not made of stone.
mnli hypothesis: The spiral staircase is not made of stone. premise: In the interior, the same exuberant artistry can be admired in the sculpted wood organ frame and the stone tracery of the spiral staircase.