Casares and Borges being renowned for their (obsessive?) fascination with the dreamer and the dream state, their 1967 collection of 'Extraordinary tales' bring together a beautiful series of short stories. The oneiric quality of each is expressed and mediated by the central tale "The Pattern in the Carpet", which expresses the Queneau-esque variations on a single theme. Like any dreamer, the ensemble makes sense only when you awake from the novel and look for the patterns.
Although a translation--and therefore a translation of a translation in many cases--the careful editing of each tale avoids any sense of jarring or incongruity. Put simply, a beautiful collection of short stories. If you like Edgar Allen Poe, Kafka's Penal Colony or Great Wall, then I think you'll enjoy this.