Uploaded February 2026 | Updated September 2026, 2 weeks ago

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Ben Sparks explores hidden depths of a seemingly simple game. More on Jane Street's AMP program at jane-st.co/Numberphile-AMP-2026 (sponsor) -- More links & stuff in full description below ↓↓↓

An extra snippet on Numberphile2: youtu.be/lz2POMYd4YM
And a 4.5-minute longer version of this video can be watched by Patrons: patreon.com/posts/150089653

Ben Sparks own website (you can book him for talks and training, etc): bensparks.co.uk

More Ben on Numberphile: youtube.com/playlist?list=PLt5AfwLFPxWLDKmnxLg8477hrxY33LL6q

The game can be played without the grid at 15game.bensparks.co.uk and can be played with the magic square grid at 15game.bensparks.co.uk/gameTTT.html

Patreon: patreon.com/numberphile

Numberphile is supported by Jane Street. Learn more about them (and exciting career opportunities) at: bit.ly/numberphile-janestreet

We are also grateful for support from the Ben Delo Foundation - delo.org

NUMBERPHILE
Website: numberphile.com

Video by Brady Haran and Pete McParlan (who did the stop motion!)

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Brady's videos subreddit: reddit.com/r/BradyHaran

Brady's latest videos across all channels: bradyharanblog.com

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