Behind the Yellow Door

One day in my teenage years, I met Mr DILLE, a neighbour who later sent me an intriguing photograph with a message inviting me to visit him behind the yellow door. Mr DILLE was in fact Lutz DILLE, an eccentric artist, who has now deceased. He dedicated his life to photographing people on the streets of the world. I never responded to his invitation. What if I did meet him nonetheless?