 The square of opposition was an important tool in Aristotelian logic for understanding contradiction and other relations between pairs of assertoric predicative propositions formed with the same categorematic terms. As has been recognized, John Buridan and other logicians expanded this theory to the octagon of opposition to cover also modal propositions. Obligational disputations can be understood as an expansion into another direction. An obligational disputation abstracts from the predication as the standard form of proposition and turns from the binary logical relations into examining logical relations within a dynamically constructed sequence of propositions. (Cf. especially Dutilh Novaes 2005; 2007; 2011; Dutilh Novaes and Uckelman 2016; Strobino 2011; Uckelman 2013; Yrjönsuuri 2000; 2015.)