Literature Reference: 孔黑烟痕深，罅青苔色厚。—— 《双石》 Deep black smoke marks, thick green moss in crevices. Source from 'Shuang Shi'.
烟: Smoke, billowing clouds. Herbal essence.
痕: Imprint. Trace.
Meaning: Smoke marks symbolize the traces of time and the beauty of nature, implying depth and sedimentation.