Foil examples are also found in plays. We notice in William Shakespeare’s play “ Julius Caesar ” a twofold foil. Cassius is a foil to Brutus and Brutus is a foil to Antony. Both Cassius and Brutus conspire to kill Caesar but Cassius is more prone to treachery than Brutus is and thus easily gives in to his evil ambition. Brutus, on the other hand, hesitates to join the plot without careful analysis of the whole scenario. Cassius even goes to the extent that he does not shy away from writing phony letters to convince Brutus to join the plot. Brutus, in contrast, is bent on relying on his own reason and his awareness of his dignified obligations as a Roman to do the inevitable. Moreover, Brutus is a foil to Antony because Brutus’s honesty and simplicity are in clear contrast to Antony’s qualities of deception and over-ambition.
If we substitute for a frog a "Mr. Goodwill" or a "Mr. Prudence," and for the scorpion "Mr. Treachery" or "Mr. Two-Face," and make the river any river and substitute for "We're both Arabs . . ." "We're both men . ." we turn the fable [which illustrates human tendencies by using animals as illustrative examples] into an allegory [a narrative in which each character and action has symbolic meaning]. On the other hand, if we turn the frog into a father and the scorpion into a son (boatman and passenger) and we have the son say "We're both sons of God, aren't we?", then we have a parable (if a rather cynical one) about the wickedness of human nature and the sin of parricide. (22)