Like this is something we don't already know!
This was a photo of a photo of a railing in a Philadelphia building. Tangling in wrought iron... somehow all that banging might work against the quiet serenity of making a Zentangle.
I snappped another photo of a building in University City that has a fabulous piece of work on it. Unfortunately, the photo was blurry. I think I must have had the setting on my camera dialed in for close up work. Next time I'm there, I'll shoot it again.