Slow observer
After living in this house for
exactly 20 years as of today, I just now noticed that the metal siding is embossed in a simulated wood pattern. I'd always thought of it as smooth. Why did this suddenly come to my attention? Possibly because the constant wind of the last year has scoured the paint off the higher spots, making an intaglio effect.
Correction after taking another look: Actually the paint was filling in the low spots before (still is on the leeward side), and the wind has scoured out both the low spots and the high spots on the windward side to make the design visible.