IMAGE- The Klein Four-Group, 'Vierergruppe': the group's four elements in four colors. Blue, red, green arrows represent pairs of transpositions, and the four black points, viewed as stationary, represent the identity.

* Update of 8 PM Nov. 19:
   The title refers to a work by Beckett.
  "There is nothing outside itself that Quad
   might be about." — Sue Wilson.
   The Klein group is not so limited.