The “clues” under discussion in this paper would then appear to be so much free communication to be taken advantage of; and it is an empirical question what free communication a rational player should be able to find and take for granted. Just as esthetic or syntactic constraints on a language help to eliminate garbles in a badly transmitted message, esthetic or dramaturgical constraints, casuistic or geometric constraints, can help to eliminate ambiguousness in a situation where tacit concerted choice is required.

Thomas C. Schelling, The Strategy of Conflict, loc. 680