TWO BY TWO by David Garnett. 144 pages. Atheneum. $3.50.
Elaboration of ancient fables has always been a fascinating literary exerciseparticularly because a fable, if it is classic, sends the imagination soaring far beyond its own spare telling. Thomas Mann got four dense volumes out of exploring the emotional and theocratic implications of a few chapters in the Bible describing Joseph's sojourn in Egypt. With less weight but more easy charm, British Author David Garnett has done the same thing with the story of Noah and his ark.
Garnett's heroines are 14-year-old twin sisters, Fan and Niss, who have managed to stow away...