Over the centuries, simple caves began to resemble free-standing buildings, needing to be formally designed and requiring highly skilled artisans and craftsmen to complete. These artisans had not forgotten their timber roots and imitated the nuances of a wooden structure and the wood grain in working with stone.
The passage describes a shift from basic cave dwellings to more elaborate structures that required formal planning and skilled artisans. The artisans' experience with timber construction influenced their approach to working with stone, mimicking the nuances of wood grain.