Puzzles with beautiful solutions

Total watch time

9h 51m

at 1× speed · exactly 9 hours, 51 minutes at 1×

custom

1×	9h 51m
1.25×	7h 52m 48s
1.5×	6h 34m
1.75×	5h 37m 43s
2×	4h 55m 30s

Average video21m 6s

Longest51m 56s

Shortest7m 27s

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About 10 days at an hour a day

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At one hour a day, every day, this playlist takes about 10 days. Turn on JavaScript to plan around your week.

Videos (28)

9h 51m in total · tick what you've watched

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1	The hardest problem on the hardest test	11:15	2017-12-08
2	Why colliding blocks compute pi	26:07	2025-03-13
3	This open problem taught me what topology is	27:26	2024-12-24
4	The last IMO problem AI could not solve	51:56	2026-09-18
5	Why is pi here? And why is it squared? A geometric answer to the Basel problem	17:08	2018-03-02
6	Olympiad level counting (Generating functions)	34:36	2022-05-23
7	The unexpectedly hard windmill question (2011 IMO, P2)	16:03	2019-08-04
8	But why is a sphere's surface area four times its shadow?	15:51	2018-12-02
9	Solving problems by adding a dimension	29:42	2024-11-08
10	This pattern breaks, but for a good reason \| Moser's circle problem	16:13	2023-07-02
11	A tale of two problem solvers \| Average cube shadow area	40:06	2021-12-20
12	Why do prime numbers make these spirals? \| Dirichlet’s theorem and pi approximations	22:21	2019-10-08
13	How to lie using visual proofs	18:49	2022-07-03
14	Why slicing a cone gives an ellipse (beautiful proof)	12:52	2018-08-01
15	Euler's formula with introductory group theory	24:28	2017-03-03
16	All possible pythagorean triples, visualized	14:53	2017-05-26
17	Why π is in the normal distribution (beyond integral tricks)	24:46	2023-04-02
18	The other way to visualize derivatives \| Chapter 12, Essence of calculus	14:26	2018-05-19
19	Using topology for discrete problems \| The Borsuk-Ulam theorem and stolen necklaces	19:22	2018-11-18
20	Pi hiding in prime regularities	29:43	2017-05-19
21	Thinking outside the 10-dimensional box	25:13	2017-08-11
22	The Brachistochrone, with Steven Strogatz	16:02	2016-04-01
23	The impossible chessboard puzzle	18:42	2020-07-05
24	How colliding blocks act like a beam of light...to compute pi.	14:41	2019-02-03
25	Binary, Hanoi and Sierpinski, part 1	13:59	2016-11-25
26	Binary, Hanoi, and Sierpinski, part 2	13:40	2016-11-25
27	Music And Measure Theory	13:13	2015-10-04
28	Euler's Formula and Graph Duality	7:27	2015-06-21

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Data from the YouTube Data API as of 2026-09-22 (cached). Private or deleted videos are excluded from totals.