I like the concept behind "The Pros and the Cons of hitch Hiking" by Roger Waters, the narration Is circa 40 minutes of events that happens in a dreams sequence and in reality, and It's all narrated in real time, all the titles correspond at a precise lapse of time in that 40 minutes of a night. Some Songs resemble very much others from "The Wall" like Mother, and if i'm not wrong Is because this concept was one of the two that Waters proposed to the other members, the other was of course The Wall.