Borges's story The Garden of Forking Paths can be considered to be a three dimensional chess game for a variety of reasons. First, like a game of chess, a nearly infinite number of possible outcomes are proposed through the story (just as how a chess game can allow for a variety of different outcomes). Also, chess is a game of choice, just as the Garden of Forking Paths - both the story itself and the novel of the same titles mentioned in the story - allows for the reader to, in essence, choose their own design and strategy. Furthermore, the lead character\protagonist in the story is manipulating events throughout the story to, in essence, score a "checkmate."
I think either excited or confused. Since the first sentence is well, with an exclamation point, I guess I would lean towards excited. It would help to know more of the story.
