A screenplay like Charlie Kaufman’s Eternal Sunshine of the Spotless Mind (2004) is a masterpiece of construction. It’s hard to conceive putting a film like this together. The story begins simple enough, with awkward and socially-repressed Joel (Jim Carrey) meeting extroverted and spunky Clementine (Kate Winslet) through the innocent cliché of a long walk on the beach. The two instantly attract, as tends to be the case with opposites. Joel’s voice-over narration questions why he has to fall in love with everyone who shows him the faintest bit of attention, as Clementine’s bubbling personality makes it obvious she’s rarely less than its center. While Joel makes every attempt to shutter himself from the growing magnetism of his new acquaintance, he simultaneously can’t seem to shake her. He leaves her only to end up offering her a ride home, and exits her house only to pick up the phone the minute he steps through his own door. She’s become part of him through the undefinable forces of human emotion, and it’s all before the opening credits start.

From that point, the film instantly jumps forward only to start moving backward. Joel learns that Clementine hired a company that erases memories to delete him from her brain, and in an act of retaliation, he signs up for the same treatment. The core of the film is then spent watching the downward spiral of their relationship as it retreats in time. We see how their instant chemistry ended in mutual disappointment, the personality traits that clashed, and eventually, the love they maintained for one another despite it all. The chronology begins simply enough, but as the erasing process digs deeper and brings Joel’s older memories closer to the forefront, timelines shift and weave in varying directions. Joel’s memories and conscious thoughts begin to blend, re-fabricating events from the relationship. It becomes a philosophical piece of cinematic art, and the best means of keeping track of where we are in Joel and Clementine’s relationship chronology comes down to one key element: Clementine’s hair.

When Clementine and Joel first met, her hair is an acidic shade of green. The hair is long and grown out with significant roots showing, revealing the blonde underneath, and she pairs it with a bright orange sweatshirt. Green is the color of life, of renewal, of nature. It is associated with harmony, freshness, and ambition, the presence of her roots only emphasizing the budding life of their connection. The only time we see Clementine with this hair color is at this moment, the day her and Joel first meet. It’s the blossoming of something fresh and alive; something pure and organic and derivative of human nature. It’s the birth of all that is to come—and of course, one of the final colors we see in the backwards-facing trajectory of the film.

Before their first date, Clementine changes her hair color to a bright, fiery red. Red is the color of fire and blood, associated with energy, strength, passion, and desire. It is also symbolic of warning and danger. Joel and Clementine fell for each other hard, and their infatuation was instant and powerful. Naturally, they didn’t yet know the scope of what would befall them; they existed only in the heat of something new and alive. As their story marches forward (or, backward in the case of the film), the redness of her hair fades to an orange—then, to a muddy orange, grown out again, with increased messiness. Though Clementine’s hair is never styled in any traditional sense, it’s still possible to gauge the attention she put into taming it.

It’s during the orange phase that the problems between the two start to emerge. The era of red passion has passed, and the fervor has died down. They really have to start living with one another when things are orange, and all those little personal quirks they were happy to ignore in the heat of their new romance become harder to deny. We start to see their relationship dissolve in reverse, filling in the blanks between the polarities of painful disgust and euphoric delight we’ve witnessed thus far.

Soon, the two don’t have anything to talk about. Clementine berates Joel for never sharing anything with her, and he scowls back that she never stops talking. She mentions wanting a baby, and Joel, as with most subjects, is keen to say they’ll “talk about it later.” Things spiral out of control fast for the pair, eventually resulting in Clementine making the spontaneous decision to have him erased from her mind. She’s not happy, but she is impulsive. And just like that, Joel is gone.

Following the procedure, she dyes her hair blue. “Blue Ruin,” it’s called. She does a poor job, with certain chunks colored brightly and others completely missed. It’s given less attention than her previous color changes, adding to its emotional significance. It’s under the sobering comfort of Blue Ruin that Joel and Clementine meet each other again for the first time, calling back the sequence that kicked off the film, her wearing the same orange sweatshirt as the original day on the beach. They can’t help but be drawn to each other for the same reasons as their first go-around, bringing the philosophical and emotional core of the film full circle.

Clementine’s hair is an incredibly reliable point of reference throughout the ever-changing, manipulative style of Eternal Sunshine of the Spotless Mind. The application of psychological color meanings is direct and un-missable, and becomes an important quality in a film so full of details and minutiae that can be accidentally overlooked. Before Clementine even opens her mouth in a scene, we already know how things are going to play out. We can tell her emotions before she utters a word or glances in Joel’s direction. And most importantly, it helps us keep the film’s chronology straight as it weaves in and out of fantasy and reality in a beautiful and heart-tugging way.