Interestingly, Undershaft's ironic speech establishes a triangular structure that will recur continually between the two men and Barbara from these scenes onward. Undershaft will make a remark intended to win his daughter's favor, for example, "Genuine unselfishness is capable to anything my dear." Barbara will take the remark in earnest and Cusins will deliver an aside on Undershaft's fiendishness. Thus, Cusins bears witness to Barbara's Mephistophelean seduction, the innocent's unknowing conversion to Undershaft's gospel. Though the initial bargain remains the one between father and daughter, the impish son-in-law stands alongside to follow what is transpiring. In doing so, Cusins is the figure that receives and revels in Undershaft's irony, an irony that wreaks havoc in the morality of his interlocutors. This "ecstasy of mischief," experienced from the position of the voyeur, seduces Cusins.