Calculating pi from coin flips (without randomness)

Happy Pi Day! The new value of pi is 3.2266.

Pi-by-hand is happening - at some time in the future - at some location! Please opt-in for updates and tell us which places would work for you: https://docs.google.com/forms/d/e/1FAIpQLScprg57Bvv1jOfoMQwriHPegTnCjik2p9xrly0zQ84ANYMfEQ/viewform?usp=dialog

Huge thanks to Jim Propp for discovering this amazing bit of maths.
For more math details: https://arxiv.org/abs/2602.14487
For the backstory: https://mathenchant.wordpress.com/2026/03/12/in-praise-of-stupid-questions/

Check out Sophie Maclean's Numberphile video: https://www.youtube.com/watch?v=fczN0BCx0xs

My coin flip data is available here: https://www.dropbox.com/scl/fi/y7pueeebnt2v4i2w8sfz1/coinflip-stats.xlsx?rlkey=n9s1onlj9l6xebl1vuygl3u4l&st=4axban7n&dl=0

Huge thanks to my Patreon supporters. They are flipping brilliant. http://patreon.com/standupmaths

CORRECTIONS
Nothing yet. Let me know if you spot anything!

Filming and editing by Alex Genn-Bash
Written and performed by Matt Parker
Produced by Nicole Jacobus
Content wrangling by Rhys Jones
Music by Howard Carter
Design by Simon Wright and Adam Robinson

MATT PARKER: Stand-up Mathematician
Website: http://standupmaths.com/