The road movie usually crosses the conventions of more established genres (the western, the screwball comedy, etc.) with physical narratives in motion, such as the quest -- Homer's Odyssey is one example. This type of film uses an extended episodic journey as its framework, with the story revolving around the achievement of a goal, or an arrival at a particular destination, be it physical, spiritual or psychological. Typically, within this nearly plotless framework, the characters learn something valuable about each other and/or themselves along the way. The road itself takes on both physical and metaphorical meanings in these films, often being used to represent freedom, rediscovery, and an outlet from the traps of society's imposed rules and laws. Historically, this type of film crosses international boundaries. Early examples came from the Hollywood Studio system and usually blended the open road with other established genres -- Sullivan's Travels blended the road with screwball comedy, while The Grapes of Wrath had elements of melodrama and the western. In film noir, the road movie found a sub-genre in the lovers-on-the-lam, with films that present couples on the run specifically from the law and generally from society itself (Gun Crazy, and later examples like Badlands and Wild at Heart). With the arrival of modernism, the road movie turned existential. Pierrot le Fou and other films of the French New Wave used the road as a way to escape the conventions of traditional plot. Wim Wenders's Kings of the Road used the structure to examine problems of identity in post-war Germany, while young American directors of the ‘70s used this formless genre to paint a picture of social unrest and generational change in classics like Easy Rider and Five Easy Pieces.