Question: Who sometimes known under the pseudonym "Designer X",  Callie Thorne or Greg Costikyan ?
Sentence (from "Paranoia (role-playing game)"): "Paranoia" is notable among tabletop games for being more competitive than co-operative, with players encouraged to betray one another for their own interests, as well as for keeping a light-hearted, tongue in cheek tone despite its dystopian setting.
Relevant evidence: No