i think rey represent a sort of old and more humanist view of the world . the sac be a throwback to this . it also lend him a sort of imagery and a a worker and a man who make it on his own . the girl and be the new world and of terrorism and nudity and frigidity . at the end and the two have join . he have give up his sack and she have give up her virginity . their game be over . the end scene be shoot in silence till the very end . the explosion and perhaps it indicate bunuel negative view of the future . i always get throw off by these great 70 movie . the color printing be so bad and it look comical . why do you have to put 10 line of text . that daft .