The Solitary Twin

 I read The Solitary Twin by the late Harry Mathews. Mathews was the only novelist among the prominent New York School writers, and the only American member of Oulipo. 

 There are identical twins living in a New England fishing village. A group of several people try to figure out why they have a strange (non)relationship.  They have parallel habits but are never seen together, living on opposite ends of town. The people tell one another odd stories, that end up being (non)coincidentally pertinent to the main narrative.  I can't tell whether there is a concealed Oulipean constraint in the work.  

The whole thing can be read in an afternoon (113 pages).