Although details, such as the superlaser's location, shifted between different concept models during production of Star Wars, the notion of the Death Star being a large, spherical space station over 100 kilometers in diameter was consistent in all of them. George Lucas gave the original task of designing a "Death Star" to concept artist and spaceship modeler Colin Cantwell, who had collaborated with Stanley Kubrick on the 1968 film 2001: A Space Odyssey. In a 2016 interview, Cantwell related that "I didn't originally plan for the Death Star to have a trench, but when I was working with the mold, I noticed the two halves had shrunk at the point where they met across the middle. " As it "would have taken a week of work just to fill and sand and refill this depression," Cantwell suggested a trench to Lucas to save the labor. Lucas liked the idea, and the Death Star model was created by John Stears. The buzzing sound counting down to the Death Star firing its superlaser comes from the Flash Gordon serials. Portraying an incomplete yet powerful space station posed a problem for Industrial Light & Magic's modelmakers for Return of the Jedi. Only the front side of the 137-centimeter model was completed, and the image was flipped horizontally for the final film. Both Death Stars were depicted by a combination of complete and sectional models and matte paintings.