A spokesman for the Royal Air Force Museum London suggested in 1977 that Chad was probably an adaptation of the Greek letter Omega, used as the symbol for electrical resistance; his creator was probably an electrician in a ground crew. "Life" suggested that Chad originated with REME, and noted that a symbol for alternating current resembles Chad (a sine wave through a straight line), that the plus and minus signs in his eyes represent polarity, and that his fingers are symbols of electrical resistors. The character is usually drawn in Australia with pluses and minuses as eyes and the nose and eyes resemble a distorted sine wave. "The Guardian" suggested in 2000 that "Mr. Chad" was based on a diagram representing an electrical circuit. One correspondent said that a man named Dickie Lyle was at RAF Yatesbury in 1941, and he drew a version of the diagram as a face when the instructor had left the room and wrote "Wot, no leave?" beneath it. This idea was repeated in a submission to the BBC in 2005 which included a story of a 1941 radar lecturer in Gainsborough, Lincolnshire, who drew the circuit diagram with the words "WOT! No electrons?" The RAF Cranwell Apprentices Association says that the image came from a diagram of how to approximate a square wave using sine waves, also at RAF Yatesbury and with an instructor named Chadwick. This version was initially called Domie or Doomie, and "Life" noted that Doomie was used by the RAF. REME claimed that the name came from their training school, nicknamed "Chad's Temple"; the RAF claimed that it arose from Chadwick House at a Lancashire radio school; and the Desert Rats claimed that it came from an officer in El Alamein.