Deciphering the Sandstone

I worked the fine bristles of the field brush directly into the recessed carvings of a sandstone fragment resting on the prep bench. Packed grit and old dust resisted at first, but steady, light sweeps cleared the grooves without scratching the porous surface. What looked like mere decorative scrollwork from a distance resolved into a clear tally system—three notched strokes marking storage intervals along an ancient irrigation route. I blew away the loose powder, felt the clean edge to confirm the stone's stability, and committed the sequence to memory before the floor patrol resumed.