Three Laws of Robotics card-readers in "The Caves of Steel" have a capacity of only a few kilobytes per square centimeter of storage medium. "Aurora", in particular, presents a sequence of historical developments which explains the lack of nanotechnology — a partial retcon, in a sense, of Asimov's timeline. There are three Fourth Laws written by authors other than Asimov. The 1974 Lyuben Dilov novel, "Icarus's Way" (a.k.a., "The Trip of Icarus") introduced a Fourth Law of robotics: Dilov gives reasons for the fourth safeguard in this way: "The last Law has put an end to the expensive aberrations of designers to give psychorobots
Sci-Fi (G.I. Joe) set up a battle scene between the Joes and Cobra. As he imagined the characters in his head, he described four of the Joes on front lines of the battle: Hawk, Leatherneck, Wet Suit, and Sci-Fi "stood in procession, weapons raised, adrenaline pumping feverishly. Anxious for another victory over the dreaded Cobra." He described how "Sci-Fi's lackadaisical attitude was in check today. The laser trooper in the neon green jumpsuit was leading the charge. Out front, it would be his battle cry that the enemy would hear first." Sci-Fi (G.I. Joe) Sci-Fi is a character from the toyline, comic books