The Irish mathematical physicist, J. L. Synge, invented this game. (I believe that he is cousin of the famous Irish dramatist, John Millington Synge, known for his tragic one-act play, Riders to the Sea, and his funny three-act comedy, Playboy of the Western World. The first presentation of this play by The Irish Abbey Theatre provoked a riot by the viewers who thought it maligned the Irish charcter.)

Synge cowrote a book on analytical dynamics, which was my texbook at Columbia University. He is known to many mathematical physicists for showing that quantum equations involving spin can be written in terms of quaternions (math created by his fellow Irishman, William Rowan Hamilton (1805-1865).)

Many years ago, Synge wrote a delightful little book of essays which included an essay about the game of "Circ", created to show the fallibility of language.

Two or more persons compete in "Circ", each armed with a copy of the same standard dictionary, under the supervision of a "referee". The referee chooses a defined word in the dictionary that is defined only in terms of several synonyms. At "Go", the contestants begin. Each chooses to look up one of the synonyms, which is therein defined in terms of several synonyms, one of which (when looked up) is defined in terms of several synonyms, one of which (when looked up) is .... The first person to return to the originally assigned word cries out "Circ!" (for "going in a circle") and the game ends.

I've played the game several times with friends and fellow students. You'd be surprised at the "circularity" of our language.

The loop here happens, of course, because you stay in the realm of words or names. If you shifted outside language to the world of referents, the process would abruptly end, as in that pewparordering graph.