prepositions

The following is a sample, and I'd call it a fairly representative one, of a single sentence from an article I have to read this week as homework for my film class.

"Endlessly interactive, his films can only be understood in terms of their adaptation of the generic conventions of the documentary to the tradition of black gay and lesbian self-representation of which they are a part."

Oh my god. It's like one of those Russian dolls, except with prepositions.