I recall reading a McDonnell Douglas publication (Know Your DC10?) explaining the decidely gull wing apearance of a DC10 wing when viewed from the rear as being entirely due to landing gear considerations ie. trying to reduce the length of the main gear by getting the structural attachment points as close to the ground as possible to save weight and to reduce the length and volume of the space required to hold the retracted gear. Some aircraft eg. A330/340 and DC10 have a distinct "bend" in the inboard rear spar giving a gull wing effect whereas others (747, L1011) have a more blended transition.