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Grant Sanderson

@3blue1brown.com
20K followers 18 following 53 posts

Math videos

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Grant Sanderson @3blue1brown.com · 18/09/2026
The last IMO problem AI could not solve. For when you want to sit down for a longer problem-solving saga, here's the full video: youtu.be/Nbwv5wHQoj0
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Grant Sanderson @3blue1brown.com · 12/06/2026
Here's an excerpt from the most recent video on how Shannon studied the entropy of English, animated by Mitchell Zemil
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Grant Sanderson @3blue1brown.com · 10/06/2026
@quantabooks.org just released their first book, on the story of Lean by @kevinhartnett.bsky.social. It's a great story, about a pretty significant part of what's happening in math right now. www.quantabooks.org/books/the-pr...
quantabooks.org
The Proof in the Code - Quanta Books
The inside story of Lean, a computer program that answers the age-old question: How do you know if something is true?
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Grant Sanderson @3blue1brown.com · 10/06/2026
Suppose you wanted to reinvent the idea of Shannon Entropy for yourself. This puzzle is a good place to start (Full video on YouTube).
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Grant Sanderson @3blue1brown.com · 22/03/2026
This video was a complete joy to make. Here's a short preview, but next time you're looking to sit down for 45 minutes of math and art, take a look at the full version on YouTube: youtu.be/ldxFjLJ3rVY
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Grant Sanderson @3blue1brown.com · 14/03/2026
Ah! Correction, as several have pointed out, it should be 4 in the taxicab metric. And the same correction, i.e., measuring the circle in the appropriate metric, the relevant date-shifting-joke-value to be closer to 2.6
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Grant Sanderson @3blue1brown.com · 14/03/2026
Anyway, the video I was hoping to have out this day will be out closer to the 20th. Some call it “missing your deadline”, but I prefer to think of it as giving the L_{2.2} norm a little love.
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Grant Sanderson @3blue1brown.com · 14/03/2026
Happy Pi Day! In a certain sense, π is not a constant, but a variable. Using our usual Euclidean distance, it is 3.14159… but applying other L^p norms on ℝ², half the unit circle's perimeter will give other values. For instance, at p=1 (taxicab geometry), “π” = 2√2. At p ≈ 2.2, it's 3.20.
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Grant Sanderson @3blue1brown.com · 27/02/2026
Well, math terminology being what it is, something like this was bound to happen eventually. (If you're curious about why these balls are so puny, the full talk is up on YouTube)
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Grant Sanderson @3blue1brown.com · 31/01/2026
New video! Memorable for its delightfully absurd name, the Hairy Ball Theorem is extremely beautiful and has some surprising applications: youtu.be/BHdbsHFs2P0
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Grant Sanderson @3blue1brown.com · 20/01/2026
The Ladybug Clock puzzle
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Grant Sanderson @3blue1brown.com · 07/11/2025
I had fun joining @peterrowlett.net and @steckl.es recently on their mathematical objects podcast, talking about my wood puzzle collection. Most of the time was spent struggling desperately to describe a highly visual topic in an audio-only context. open.spotify.com/episode/0rRM...
open.spotify.com
Mathematical Objects: 3D wooden puzzle with Grant Sanderson
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Grant Sanderson @3blue1brown.com · 05/11/2025
The next video in the Laplace Transform sequence is up! youtu.be/FE-hM1kRK4Y Here, we dig into a concrete example, the forced oscillator. Some of you may remember that this was relevant for studying why light slows down in a medium.
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Grant Sanderson @3blue1brown.com · 12/10/2025
Ever since I made a video about Fourier Transforms, one of the most requested topics on the channel has been its close cousin, the Laplace Transform. I've been having a lot of fun animating a mini-series about this topic, and the main part is now out. youtu.be/j0wJBEZdwLs
youtu.be
But what is a Laplace Transform?
YouTube video by 3Blue1Brown
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Grant Sanderson @3blue1brown.com · 18/09/2025
In the fifth and final of a series of guest videos I've been posting, @BenSyversen delves into a question anybody who has had to do ruler and compass constructions in a geometry class may have wondered: What's the point?
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Grant Sanderson @3blue1brown.com · 18/09/2025
Much of Euclid’s Elements is easily misunderstood. Some proofs seem to have logical gaps. Some constructions seem pointless, others seem needlessly convoluted. Each of these provides a window into how the ancient Greeks thought about math and the philosophical role that geometry played.
youtu.be
Why ruler and compass? | Guest video by ⁨@bensyversen⁩
YouTube video by 3Blue1Brown
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Grant Sanderson @3blue1brown.com · 07/09/2025
New video about a piece by the modern artist Sol LeWitt, and the group theory behind it. youtu.be/_BrFKp-U8GI
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Grant Sanderson @3blue1brown.com · 28/08/2025
Guest video 3/5 while I'm on leave is now up! It's by a former SoME winner, covering key ideas in statistical mechanics to create a simple and discrete model mirroring the behavior of a fluid transitioning between a liquid and gaseous state. Enjoy! youtu.be/itRV2jEtV8Q
youtu.be
Simulating Phase Change | Guest video by Vilas Winstein
YouTube video by 3Blue1Brown
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Grant Sanderson @3blue1brown.com · 23/08/2025
Hey, psst, you can find early views for two upcoming guest videos on Patreon, one about statistical mechanics and another covering a story of modern art and group theory. Notes on early releases are always helpful before finalizing a video. www.patreon.com/posts/explor...
patreon.com
Exploration & Epiphany (Early view) | 3Blue1Brown
Get more from 3Blue1Brown on Patreon
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Grant Sanderson @3blue1brown.com · 25/07/2025
For context, I knew I'd want to take some time away this year (paternity leave!), so I reached out to a few other creators whose work I respect and asked if they'd be interested in me commissioning a guest video during my absence. It's a pretty good lineup coming!
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Grant Sanderson @3blue1brown.com · 25/07/2025
New video on the details of diffusion models: youtu.be/iv-5mZ_9CPY Produced by Welch Labs, this is the first in a short series of 3b1b this summer. I enjoyed providing editorial feedback throughout the last several months, and couldn't be happier with the result.
youtu.be
But how do AI videos actually work? | Guest video by @WelchLabsVideo
YouTube video by 3Blue1Brown
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Grant Sanderson @3blue1brown.com · 04/05/2025
In the most recent video about quantum computing, I saw many comments expressing a similar point of confusion regarding Grover's algorithm. I made a follow-up to (hopefully) clarify some of the issues and to address a few other under-emphasized points. youtu.be/Dlsa9EBKDGI
youtu.be
Where my explanation of Grover’s algorithm failed
YouTube video by 3Blue1Brown
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Grant Sanderson @3blue1brown.com · 30/04/2025
To get around the question P=NP, and whether some clever analysis of the gates could also reveal the answer, the framing here is to assume the only thing you can do with the function is try it out on inputs.
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Grant Sanderson @3blue1brown.com · 30/04/2025
That part of the video could have been better phrased. For any problem you'd want to use this for, you would know the gates, so it's not a black-box in that sense. But to have a catch-all stand-in example, I want to presume there's no insight you gain about the answer by analyzing those gates.
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Grant Sanderson @3blue1brown.com · 30/04/2025
It's known you cannot do better than O(√N), which is certainly not as earth-shattering as an exponential speed-up would be, and questionably useful given the enormous overheads of quantum computing. Nonetheless, it's thought-provoking that such a thing is possible!
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Grant Sanderson @3blue1brown.com · 30/04/2025
If you translate this setup into a quantum computer (explained in the video), Grover's algorithm offers a "faster" way to do this, in that it's O(√N).
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Grant Sanderson @3blue1brown.com · 30/04/2025
As a generic stand-in for the kind of problem it solves, suppose you have a function acting on {1, ..., N} which returns True on one and only one value in this set. If all you can do with this function is try it out on numbers, then it takes an average of (1/2)N steps to find the answer.
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Grant Sanderson @3blue1brown.com · 30/04/2025
What do they do then? This video builds up to Grover’s algorithm, a general method in quantum computing for finding solutions to any NP problem, i.e., anything where you have a quick way to verify solutions, even if finding them in the first place may be hard.
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Grant Sanderson @3blue1brown.com · 30/04/2025
A common misconception about quantum computers is that they would solve hard problems by trying all possible solutions in parallel. This vaguely gestures at something true, but the reality is more subtle.
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Grant Sanderson @3blue1brown.com · 30/04/2025
New video! This covers the fundamentals of quantum computing and builds up to a step-by-step walk-through of an important algorithm in the field. youtu.be/RQWpF2Gb-gU
youtu.be
But what is Quantum Computing? (Grover's Algorithm)
YouTube video by 3Blue1Brown
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Grant Sanderson @3blue1brown.com · 13/03/2025
I hope so too, the thought of a high school teacher using this idea for a lesson was a key motivator in the back of my mind.
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Grant Sanderson @3blue1brown.com · 13/03/2025
The most viewed thing I've ever made is a short about two colliding blocks computing π. I just made a new edition of the explanation for why π shows up there, setting things up for a (coming soon) follow-on connecting it to quantum computing. youtu.be/6dTyOl1fmDo
youtu.be
There's more to those colliding blocks computing pi
YouTube video by 3Blue1Brown
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Grant Sanderson @3blue1brown.com · 26/02/2025
If you do this, you can reach out to the channel via this page. 3blue1brown.com/contact Be sure to have a link to footage of the experiment. If anyone can get it to work with 100-to-1, I'd be happy, and if anyone can do it for 10,000-to-1, I'd be both delighted and amazed.
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Grant Sanderson @3blue1brown.com · 26/02/2025
More generally, with a mass ratio of N-to-1, the number of collisions is around π / arctan(1 / sqrt(N)). So any big mass ratio gives you an approximation of pi by multiplying the number of collisions by arctan(1/sqrt(N))
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Grant Sanderson @3blue1brown.com · 26/02/2025
Note, there's no reason to restrict yourself to powers of 100. For example, you could use powers of 4 to compute pi in binary. A mass ratio of 64-to-1 should give 25 collisions, which is 11001 in binary, and pi looks like 11.001...
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Grant Sanderson @3blue1brown.com · 26/02/2025
Also, it's a wildly inefficient way to compute pi. To even get "3.14" you'd need this to work with a 10,000-to-1 mass ratio and have a way to count all 314 collisions. Matt Parker and I actually gave this a go, and the results were...okay, but could definitely have been improved :)
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Grant Sanderson @3blue1brown.com · 26/02/2025
The original puzzle assumes zero friction and zero energy loss in collisions, so obviously there are limits to how far you can get. I can tell you the real limiting factor is energy lost in collisions, more so than friction. The hardest part is energy lost in collisions, more so than friction.
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Grant Sanderson @3blue1brown.com · 26/02/2025
Many years ago I made this video about how two colliding blocks on a frictionless plane can compute pi. My challenge to you is simple: Implement this in practice.
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Grant Sanderson @3blue1brown.com · 26/02/2025
I have a pi-day challenge for all the physics students among you (or anyone willing to set up an experiment). If you share your results with me by March 10th, I may feature them in a video, depending on how good the results are and how many I get.
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Grant Sanderson @3blue1brown.com · 25/02/2025
Lol
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Grant Sanderson @3blue1brown.com · 23/02/2025
Part 2 of the collaboration with Terence Tao on the cosmic distance ladder is now out. It covers how we first learned the distances to planets, stars, and galaxies far, far away. youtu.be/hFMaT9oRbs4
youtu.be
The cosmic distance ladder with Terence Tao, part 2
YouTube video by 3Blue1Brown
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Grant Sanderson @3blue1brown.com · 08/02/2025
New video! Terence Tao on how we measure the cosmos: youtu.be/YdOXS_9_P4U
youtu.be
Terence Tao on how we measure the cosmos | Part 1
YouTube video by 3Blue1Brown
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Grant Sanderson @3blue1brown.com · 06/02/2025
I've had fun editing together on a very different kind of video from the norm. Keep an eye out this weekend.
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Grant Sanderson @3blue1brown.com · 24/01/2025
Holograms! Easily my favorite project from last year. Full video: youtu.be/EmKQsSDlaa4
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Grant Sanderson @3blue1brown.com · 24/12/2024
Aside from animating this beautiful piece of math better, I had an itch to address new research that’s happened since, and to pull in numerous other mind-bending connections.
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Grant Sanderson @3blue1brown.com · 24/12/2024
Well, perhaps not “new” new. Books have a notion of a second edition, and while YouTube videos usually don’t, I wanted to make a new edition of one of the earliest videos on the channel, as this is one of my favorite pieces of math.
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Grant Sanderson @3blue1brown.com · 24/12/2024
New* video! If you’ve ever wondered what topology is, this problem is one of the best examples I know of to give an authentic sense of what it’s all about: youtu.be/IQqtsm-bBRU
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Grant Sanderson @3blue1brown.com · 03/12/2024
I fully hope to pick it back up again one day, but in the mean time, Vince and I wanted to share some nice pieces produced during that time intended to serve as the soundtrack.
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Grant Sanderson @3blue1brown.com · 03/12/2024
It would make a great video, and ultimately an overwhelming amount of scope-creep led me to set it aside for a while for my own sanity.
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Grant Sanderson @3blue1brown.com · 03/12/2024
The full story and broader context is not as well known, and has been confused by apocryphal tales and twisted narratives over the years. This piece by Tony Rothman is a pretty good start for anyone curious: sites.tufts.edu/histmath/fil...
sites.tufts.edu
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