Geoff Manaugh, the creator of the BldgBlog site and author of “The BldgBlog Book,” discusses “how architecture and fiction overlap, where architectural ideas may be better expressed in fiction than in the built form, and conversely where fiction plays an analytic role in the pursuit of architectural ideas.” Manaugh discusses the fiction of China Miéville, student work from Columbia University, and Stephen T. Asma’s “On Monsters.” He characterizes the myth of Alexander’s Gates, associated with the Caucausus Mountains, as an architectural folktale about the creation of barriers against the Other. He talks about the 1984 movie “Ghostbusters,” and Soviet fantasy writer Sigizmund Krzhizhanovsky’s short story “Quadraturin.”