Around 1915, Danish psychologist Edgar Rubin developed his vase illusion (sometimes known as the figure-ground vase), an intentionally ambiguous visual tool for studying human figure-ground perception. It is known informally as the “Rubin vase” because the central image is a vase or goblet, in this case filling the white space. But if you focus on the black background around the vase, it usually takes very little time for that “background” to morph into two black faces in profile, their noses almost touching each other.

One of our brain’s jobs is to interpret visual patterns in the eye created by external objects. To do this effectively, we need to be able to distinguish objects from their background. Rubin’s vase illusion is a tool that marks human changes in perception: the viewer may see the foreground as primary and the background as secondary, or visa versa.

We storytellers often build our narratives by tracking “the light”—in this case I’m using “light” to refer to the arc of our protagonists or heroes. Sometimes we focus on light to the point of excluding all but the most superficial consideration of the dark forces of antagonism opposing our protagonists.

But viewing images of Rubin’s vase can remind us that we have a powerful tool we sometimes forget to use. We can freshly envision our stories by shifting our focus from the primary object or “light” (the protagonist), and refocus our attention on the ground/background or “dark” (the antagonist/forces of antagonism). When we do this the antagonist appears suddenly in focus like Rubin’s “faces.”

If you were one of the millions of TV fans hooked by the long-running series, DEXTER, based on the bestselling books by Jeff Lindsay, you’ve experienced getting seduced to the dark side—in this case Dexter’s viewpoint, his code of honor, his locus of “right”.  The twist here: serial killer Dexter is the protagonist.

Not every story has a villainous antagonist (and very few have a psychopathic protagonist), but all stories must have forces that act upon, stand in the way of, challenge and push back against a hero yearning and acting to reach her goal.  Forces of antagonism may include human (alien, zombie) foes, social, political and historical forces, forces of Nature, and the protagonist’s internal antagonists, such as false beliefs, self-delusions, demons, hungry ghosts, and old emotional wounds or trauma—all the old baggage.

I’ve had writers tell me they hate seeing their characters suffer—and while I understand that protective impulse, I also know it must be avoided at all costs. Readers come to know and identify with characters by watching them make the hardest choices under increasingly intense pressure.

If you don’t believe me, follow Kurt Vonnegut’s Rule #6: “Be a sadist. No matter how sweet and innocent your leading characters, make awful things happen to them—in order that the reader may see what they are made of.”

Our antagonists have immense potential to drive our heroes, challenge them at every turn, and push them to the ultimate test—in the process causing our protagonists to build new capacities to face challenges and to forge resilience while propelling our stories to compelling and satisfying endings.

By fully exploring the arc of opposition in all its forms—as well as we explore the arc of our hero—we may find that the crafting and drafting of our stories comes more quickly, with more ease, and, ultimately, with more fully realized characters, than if we focus more exclusively on protagonist alone.

Ultimately, storytelling is a dance between yin and yang, dark and light. So let your imagination dance between those energies, just as your eyes dance between Rubin’s figure and ground, his vase and faces.