How often do a clock's minute and hour hands cross? Featuring Cliff Stoll..... See Objectivity at: www.youtube.com/c/ObjectivityVideos More links & stuff in full description below ↓↓↓ More Cliff videos: bit.ly/Cliff_Videos Cliff Stoll's Klein Bottle store: www.kleinbottle.com 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. 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 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