Old Observatory Stairwell

Iron steps wind upward through a round observatory tower, cutting a dark curve through worn stone walls. A small opening at the top brings in blue daylight, while masonry changes from broad shadow to pale blocks around the bend.

Build the stair rail and repeated treads first; their curve gives neighboring pieces a reliable direction. Sort stones by mortar lines and shade, then use the sky opening as a compact finishing anchor. Worn tread edges repeat at different angles, so each step still offers a small directional clue.