I’ve always loved the visual effect of torn layers – billboards layered with posters, one on top of another, some ripped back to expose older ones beneath, and I once looked after an old house which had layers and layers of ancient wallpapers – some dating back as far as the 18th century. For me, such layers are almost a metaphor for time, and I think I love not just the beauty of the visual effect but also the almost archaeological thrill of discovering what lies beneath, of peeling back the layers so that you get a glimpse revealed of  something older, earlier, deeper.     It also makes a…