Grant Sanderson didn't mean to become the internet’s favorite math teacher. It kinda just happened. About a decade ago, he started tinkering with a Python library he wrote called Manim—short for Mathematical Animation—because he was bored with how static and lifeless textbooks felt. He wanted to see the math move. What resulted was 3Blue1Brown, a YouTube channel that has fundamentally shifted how millions of people think about calculus, linear algebra, and neural networks.
It’s a weird phenomenon. You sit down to watch a twenty-minute video on the Basel problem or the weirdness of Quaternions, and suddenly, you’re nodding along like you’ve got a PhD from Princeton. Sanderson has this uncanny ability to strip away the "syntax" of math—the scary symbols and rigid proofs—to show you the "semantics." The meaning. He basically treats math like a visual language rather than a set of rules to memorize.
The Manim magic and why it works
Most of us grew up with math being a chalkboard nightmare. It was dry. It was dusty. Sanderson changed that by making math look like art. He uses his custom software to create these fluid, organic movements where vectors don't just sit there; they stretch and rotate.
The software itself, Manim, is open-source now. It’s actually become a bit of a cult classic in the developer community. People use it to explain everything from physics to computer science because it focuses on "programmatic animation." Instead of clicking and dragging shapes in a video editor, you write code to define how objects relate to each other. If you change a variable, the whole animation updates perfectly. That’s why his videos feel so precise. They aren't just illustrations of the math; they are the math, rendered in real-time.
Honestly, the secret sauce isn't just the code. It’s the pacing. Sanderson often spends five minutes just setting up a single intuition. He’ll ask a question that seems simple, then slowly peel back the layers until you realize you’re looking at something incredibly profound. He calls this "the essence." You aren't just learning how to calculate a derivative; you're learning what a derivative feels like in a physical space.
What 3Blue1Brown gets right about the "Essence of Linear Algebra"
If you’ve ever taken a college-level math course, you probably remember the "Essence of Linear Algebra" series. It’s arguably his most famous work. For years, students were taught that a matrix is just a box of numbers. You multiply this row by that column, carry the one, and hope you didn't make a typo.
3Blue1Brown flipped the script.
He showed that a matrix is actually a transformation. It’s a way of warping space. When you multiply a vector by a matrix, you aren't just doing arithmetic; you’re literally moving the entire grid. Seeing the grid lines bend and skew makes the concept of a "determinant" (which usually feels like a random formula) suddenly make sense as the "area of a transformed square."
It’s visual storytelling.
It’s also why he’s become a staple in AI education. You can’t really understand how a Large Language Model works without understanding high-dimensional vectors. When people watch his series on Neural Networks, they finally see the "gradient descent" not as a calculus nightmare, but as a ball rolling down a hill in a landscape of cost functions.
The "pi" in the most unexpected places
One of the coolest things about the channel is how Sanderson finds connections where they shouldn't exist. Take the video about colliding blocks and the digits of $\pi$.
It sounds like a fake clickbait title, right? Two blocks bounce off each other, and if one is way heavier than the other, the number of total bounces perfectly matches the digits of $\pi$. $3, 1, 4, 1, 5...$ It’s mind-blowing.
But Sanderson doesn't just show you the trick. He explains the "why" by mapping the physics problem onto a circle. It turns out that the conservation of energy and momentum creates an elliptical path in "velocity space." By transforming that ellipse into a circle, the $\pi$ naturally emerges. This is the hallmark of 3Blue1Brown: taking a confusing "magic trick" and showing you the hidden machinery behind the curtain.
The human behind the brown eye
The name "3Blue1Brown" comes from a weird biological quirk Sanderson has: a brown sector in one of his blue eyes (heterochromia). It’s a fittingly specific detail for someone who obsesses over the minutiae of geometric proofs.
Before he went full-time on YouTube, Sanderson worked at Khan Academy. You can still see his influence there. He helped them move toward more conceptual, less "rote" learning. But YouTube gave him the freedom to spend a month—sometimes two—on a single video. That kind of obsession is rare. In a world of fast-paced "edutainment" and 60-second TikTok explainers, 3Blue1Brown is a slow-burn.
He’s also not afraid to admit when something is hard.
He often prefaces complex topics by saying something like, "If this feels unintuitive, that’s because it is." He validates the learner's struggle. That’s a huge part of his E-E-A-T (Experience, Expertise, Authoritativeness, and Trustworthiness). He isn't some distant professor lecturing from a podium; he’s a guy who clearly loves the puzzle and wants you to love it too.
Why some critics (actually) push back
It's not all universal praise, though. Some math purists argue that 3Blue1Brown makes things "too easy." The "illusion of competence" is a real thing in education. You watch a video, you feel like you understand it, but then you try to solve a problem on paper and realize you’re lost.
Sanderson has actually addressed this. He’s encouraged viewers to pause the video, grab a pen, and try to predict the next step. Watching isn't the same as doing. He’s the first to tell you that his videos are a "supplement," not a replacement for getting your hands dirty with real equations.
Another critique is the "over-optimization" of visuals. Sometimes, the beauty of the animation can distract from the logical rigor. But for the 6 million+ subscribers on the channel, that's a trade-off they're willing to make. Most people aren't looking to become mathematicians; they’re looking to stop being afraid of math.
The ripple effect on STEM education
The impact of 3Blue1Brown goes way beyond YouTube. You see his "style" everywhere now.
- The "Lockdown Math" series: During the pandemic, he did live sessions that felt more like a community hang-out than a lecture.
- Summer of Math Exposition (SoME): He started a competition to encourage other people to make math content. It’s created a whole ecosystem of "mini-Sandersons" like Primer or Reducible.
- Academic references: Professors now actually link to his videos in their syllabi. That’s a massive shift in how "formal" education views "informal" creators.
How to actually learn from 3Blue1Brown
If you're just watching these videos while eating cereal, you're missing out. To get the most out of the channel, you've gotta be active.
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First, don't binge. These aren't Netflix shows. Watch one, then walk away. Let the visual of the "linear transformation" sit in your brain for a day.
Second, look at the code. If you're a programmer, go to the Manim GitHub. See how he constructs the scenes. It’ll give you a much deeper appreciation for the geometry involved.
Third, use the "pause and predict" method. When he asks a "what do you think happens next?" question, actually think about it. If you guess wrong, that "friction" in your brain is where the real learning happens.
Math is often taught as a finished product—a polished diamond. 3Blue1Brown shows you the mining process. It shows you the rough edges, the clever tricks, and the accidental discoveries. It reminds us that math wasn't "invented" to torture students; it was "discovered" to describe the universe.
If you're ready to dive in, start with the "Essence of Calculus" series. It’s arguably the best thing on the internet for anyone who ever felt like they "weren't a math person." It won't make you a genius overnight, but it’ll definitely make you look at a circle and see something more than just a shape.
Next steps for deeper learning:
- Install Manim Community Edition: If you want to make your own math animations, the community-forked version is much easier to set up than the original.
- Follow the "Summer of Math Exposition" (SoME) winners: Check out the entries from previous years on YouTube to see how other creators are pushing the boundaries of visual math.
- Practice with Brillant.org or Khan Academy: Use 3Blue1Brown for the "big picture" intuition, then go to these platforms to actually solve the problem sets and solidify the knowledge.
- Read "Measurement" by Paul Lockhart: This book shares a very similar philosophy to Sanderson’s—viewing math as an art form and a craft rather than a chore.