Music theory is not about rules! It's about conventions!
And sometimes, those conventions aren't the best way to do things.
Take the opening of "Do You Want to Build a Snowman" from Frozen. The "correct" notation in 4/4, shown above, completely blurs the meter, the counterpoint, the rhythm, and even the genre. What's more, it's hard to play! (Catch that left hand Eb on the last 16th note of beat 1!)
But when we re-beam it to fit the three unequal beats of 8/8 rather than the more conventional 4 equal beats of 4/4, a whole galaxy of details springs to life.
Why does any of this matter? Well, this passage is not just dramatic but also a huge part of both setting up the film's narrative and establishing Anna's personality.
This song comes after that heart-wrenching scene where the troll king erases Anna's memory, to spare her the trauma of her near-death experience. As the scene comes to an end, a confused Anna watches as her sister completely shuns her by locking herself up in her room. The musical background fades into a soft, slow, descending melody, orchestrated very sparsely, a perfect depiction of the loss, abandonment, confusion, loneliness, etc. felt in this scene by both sisters.
And this lonely music moves immediately into a fast, upbeat tango as a now-older Anna races to her sister's door to invite her to play together. What a dramatic contrast! It highlights how playful, giddy, and carefree Anna has become, and makes the tragedy of her memory loss and abandonment all the more poignant.
Sure, you don't need to know any theory to feel this emotional contrast between one scene and the next. But music theory -- including a sensible, if unconventional, notation -- helps us understand that contrast on a much more nuanced level, which means we can also feel it in a more nuanced way. And it also makes it easier to perform!
Sam Zerin is a PhD student in musicology at New York University and a former lecturer in music theory at NYU, Brown University, and the Borough of Manhattan Community College. He also runs Social Media Music Theory (@SocialMediaMus1)