Будучи в стольном граде Амстердаме тебя повсюду окружают три икса. Захотелось понять как связаны амстердамские XXX c общеизвестными. Оказалось, что связи нет :(
Амстердамские кресты взяты с герба города и означают три распятия святого Андрея. Для жителей они означают три главные беды: наводнение, чума и огонь.
А те самые три XXX появились в 70-х годах:
Because the X-rating was not trademarked, anybody could apply it to their films, including pornographers, which many began to do in the 1970s. As pornography began to become chic and more legally tolerated, pornographers placed an X-rating on their films to emphasize the adult nature of them. Some even started using multiple X's (i.e. XX, XXX, etc.) to give the impression that their film contained more graphic sexual content than the simple X-rating. In some cases, the X ratings were applied by reviewers or film scholars, e.g. William Rotsler, who wrote "The XXX-rating means hard-core, the XX-rating is for simulation, and an X-rating is for comparatively cool films."
Взято с http://en.wikipedia.org/wiki/X-rated