As far as relating the visuals of the novel to Krevolin’s guidelines for adaptation, I see the bookstore visualization as a symbol for the challenge Clay must overcome. Throughout the novel, he struggles with his confidence in his abilities, but his model of the bookstore his first strong attempt at problem solving. He creates the model entirely on his own, and his skills are what helps him meet Kat, the Googler, who helps him take the next step and get access to the book scanner.
The bookstore model symbolizes Clay’s ability to overcome obstacles with the power of his mind. Instead of trying to solve the founder’s puzzle the old fashioned way, he applies his technical skills and creative thinking to solve a problem in a new, interesting, unconventional way, thereby leading us to the second act of the story.