Marquand's Representation of Boolean Functions
This Demonstration shows Marquand's rectangular representation of Boolean functions of two to six arguments.[more]
CNF = canonical normal form
DNF = disjunctive normal form
BDT = binary decision tree
ANF = algebraic normal form[less]
The first published suggestion for rectangular presentation of Boolean algebra of proposition was  as mentioned in [6, p. 43–44].
 A. Marquand, "On Logical Diagrams for Terms," Philosophical Magazine Series 5, 12(75), 1881 pp. 266–270. doi:10.1080/14786448108627104.
 R. Audi, ed., The Cambridge Dictionary of Philosophy, Cambridge: Cambridge University Press, 1995 pp. 780–782.
 L. Borkowski, Elementy logiki formalnej (Elements of Formal Logic, in Polish), 3rd ed., Warsaw: Wyd, 1976.
 L. Carroll, Symbolic Logic and the Game of Logic, New York: Dover, 1958.
 I. M. Copi and C. Cohen, Introduction to Logic, 9th ed., New York: Macmillan, 1994 pp. 214–218.
 M. Gardner, Logic Machines, Diagrams and Boolean Algebra, New York: Dover Publications, 1968.