The short answer—the general, universal answer—is that things come from all over. I saw the above plate on the inside of a streetcar tram in my city. It was strange to see, but I was more disappointed I hadn’t noticed it right away. It took several trips, even sitting close to the front wall, before I read the plate. Stuff arrives near you from everywhere and anywhere. That isn’t the point, though.
The point is that we don’t often care or even notice where things come from, but beginning to pay attention, whenever possible, is another way of opening up to noticing the things we often overlook. And noticing more is key to growing as an artist. We need to see clearly, and find details in ordinary things. That’s a puzzle piece that completes a big section in the overall creative jigsaw.