I stood outside my son’s bedroom, bundled up against the cold that was dropping a few meagre snowflakes on the morning. Camera in hand, I was snapping away happily when I caught a glimpse of my reflection in the window. The double glazing caught a pair of misaligned reflections, within which was caught yet another reflection from the infinity mirror on the far wall. You could see both the garden outside and the inside of the bedroom too; the one indistinguishable from the other to the eye that caught only the two-dimensional image on the glass.

At first glance, the eye saw what the lens sees, a single flat image. It took a few moments for the mind, filled with its knowledge and experience of the three-dimensional world, to begin to tease apart the various overlapping images and make sense of what they eye was seeing. I was conscious of…