> Kurt Vonnegut once said that there are only six types of story.

I see others quoting this here, but I'm not aware of Vonnegut actually saying this anywhere. This is the type of thing that needs a reference.

If I infer using what I know of Vonnegut and his presentations on the shapes of stories, I'd wager that he simply thought many stories fit into certain shapes but that not all stories fit into these. That is, there are stories that don't have well defined or common shapes. Plus, as we all know, Vonnegut liked to have fun. I highly doubt Vonnegut ever thought there were only <x> amount of story shapes.