This collection focuses on the familiar flying-saucer interpretation of a UFO: a rounded craft with a broad disc-like body. The titles point to variations in the silhouette and construction, including layered forms, small round windows, and different treatments of the underside and surface. "UFO" means an unidentified flying object; it describes something observed in the sky whose identity is unknown, and does not by itself establish that the object is extraterrestrial. Flying-saucer designs are a popular cultural image associated with that idea, distinct from the broader meaning of the term.