sentences:  The porch of Notre-Dame Cathedral in Paris and of Amiens Cathedral are decorated with similar small carved figures holding circular plaques with symbols of transformation taken from alchemy.The central pillar of the central door of Notre-Dame features a statue of a woman on a throne holding a sceptre in her left hand, and in her right hand, two books, one open (symbol of public knowledge), and the other closed (esoteric knowledge), along with a ladder with seven steps, symbolizing the seven steps alchemists followed in their scientific quest of trying to transform ordinary metal into gold.Another common feature of Gothic cathedrals was a design of a labyrinth, usually found in stone on the floor in a central part of the cathedral.