CAST IRON / CIRCLE / STREET SURFACE
Pattern Notes
Checks, grids, dots, ridges, and the repeated marks pressed into city metal.

Visual principle
Treat cast iron as urban graphic design: circle, border, embossing, repetition, rust, and pavement contrast rather than infrastructure instruction.
What to notice
Look at radial marks, check patterns, raised lettering, worn edges, rain-darkened metal, and the boundary between cover and street surface.
Editorial use
Use one strong circular image as the anchor, then alternate detail crops and wider pavement context.