Zandra Vinegar demonstrates a card game and how she likes to visualise a proof associated with it (involving a hedgehog). More links & stuff in full description below ↓↓↓ More videos involving cards: bit.ly/Cards_Shuffling Buy a deck of Numberphile playing cards: bit.ly/NumberphileCards Zandra is director of mathematics at Brilliant. Numberphile is supported by the Mathematical Sciences Research Institute (MSRI): bit.ly/MSRINumberphile We are also supported by Science Sandbox, a Simons Foundation initiative dedicated to engaging everyone with the process of science. www.simonsfoundation.org/outreach/science-sandbox/ And support from Math For America - www.mathforamerica.org/ NUMBERPHILE Website: www.numberphile.com/ Numberphile on Facebook: www.facebook.com/numberphile Numberphile tweets: twitter.com/numberphile Subscribe: bit.ly/Numberphile_Sub Videos by Brady Haran Patreon: www.patreon.com/numberphile Numberphile T-Shirts: teespring.com/stores/numberphile Brady's videos subreddit: www.reddit.com/r/BradyHaran/ Brady's latest videos across all channels: www.bradyharanblog.com/ Sign up for (occasional) emails: eepurl.com/YdjL9