My interpretation of a Simon Norfolk photo - WIP

I am always looking for something new to draw to push my boundaries and broaden my technique so I found this photo on Google of a tank track in the desert and to me it looks like a snakes skeleton of some kind and I just had to draw it. Simon Norfolk has taken a lot of pictures from the war in Afghanistan from what I can see and all of his pictures are very powerful.

This is my work in progress so far.