Main video: https://www.youtube.com/watch?v=bJOuzqu3MUQ See also: https://www.youtube.com/watch?v=o3QBgkQi_HA Zvezda's Numberphile playlist: http://bit.ly/zvezda_videos Zvezda's webpage: https://math.berkeley.edu/~stankova/ Epic Circles: https://www.youtube.com/watch?v=sG_6nlMZ8f4 Triangle Magic Highway: https://www.youtube.com/watch?v=wVH4MS6v23U NUMBERPHILE Website: http://www.numberphile.com/ Numberphile on Facebook: http://www.facebook.com/numberphile Numberphile tweets: https://twitter.com/numberphile Numberphile is supported by the Mathematical Sciences Research Institute (MSRI): http://bit.ly/MSRINumberphile Videos by Brady Haran Additional editing and animation by Pete McPartlan Support us on Patreon: http://www.patreon.com/numberphile Brady's videos subreddit: http://www.reddit.com/r/BradyHaran/ A run-down of Brady's channels: http://www.bradyharan.com/ Sign up for (occasional) emails: http://eepurl.com/YdjL9