This is a wonderful photo, generously encompassing the theme of the challenge. All subtlety and very deep - something I'd expect to see in my favourite gallery, though not, alas(?), on the dpc front page.
Like the composition of horse nose and hat. Don't think it would have felt the same if you'd included the whole horse. The quality of the photo left me wanting, though. I would have liked to see it a little sharper with a little more contrast.
I keep looking for the top of the horse's head! :-) I've instinctively scrolled both times I've viewed this image. I like the concept. Wish it had a tad more contrast as it's seems somewhat flat.