A couple things would've made this better (IMHO) - if the focus was on the street or at least if the street was a little more in focus and if there was much more traffic. ;-)
Nice use of the diamond/square motif. This is certainly beyond your control, but the fact that the wires are not perfectly straight bothers me. The idea is brilliant because of the subject matter in the background. The tunnel of light hinting at escape and the world beyond works very well. This images takes some work on the part of the viewer in the sense that it is almost interactive. I see more elements each time I look at it, yet it isn't cluttered. It might be easily overlooked by voters who are in a rush or unwilling to make an effort with a photo. I think it works just as well as an image that is immediately striking, if not better. Really nice work.
I'm sorry to predict this will not rate high in the challenge. However I like it. I like like it a lot. You will get comments like, "why focus on the grille? The background is more interesting.." Thing is, the picture is not about the city behind, it's complementary... It could not have been done the other way around, it's a picture of a window grille and I like it!