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.[22] 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.[19] The character is usually drawn in Australia with pluses and minuses as eyes and the nose and eyes resemble a distorted sine wave.[21] 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.[23] 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?"[18] 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.