With the already-busy black/white patterns, I find the tilted horizon just a bit too distracting. Maybe a little less tilt? Had to look pretty hard to notice the tack. Good shot, otherwise!
My eye went straight to the tack on this! I sat here for a few min looking at how much there is in this photo and how small and seemingly insignificant the tack is. This picture says a lot for leadlines and utilization of the rule of thirds. I'm wondering how many comments you are getting about the tack being too hard to find. I had no trouble at all. I find this to be an interesting study. I wonder if I were looking at this picture without the topic in my head if I would still see the tack as quickly as I did. The Eye goes 1st to the large dark patch in the upper left and then follows the leadlines and stops on the tack at the rule of 3rds. Remarkable use of lines and spots to bring such a great amount of attention to such a small area of the picture. 10