This is pretty much what I saw back in 1977 - a fence winding downhill towards the beach. I couldn't sketch it and I couldn't understand why not. I'm still not sure why not- possibly just a bad day.

 This is what I worked out in order to understand the perspective. Basically a mathematical approach - sine curves at different frequencies and phases. This is what I finally drew some 25 years later when I got around to it. It's not that I am an artist, the point is that by approaching the subject with math, it could be grasped, held in memory and recreated without too much difficulty after that period of time.(Scanned into photoshop and used emboss filter)