The Great Courses Plus free trial: http://ow.ly/RJw3301cRhU
Cliff Stoll discusses a "Remarkable Theorem", Gaussian curvature and pizza.
Postscript note from Cliff: "Cliff says he forgot to mention that at each point, he calls an outward going curve positive, and an inward going curve negative. He also neglected to say that saddle points have negative Gaussian curvature. Finally, he insists that the frozen pizza shown in this video is inferior to his wife's homemade pizza. But both have zero Gaussian curvature."
Animation by Pete McPartlan.
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
Support us on Patreon: http://www.patreon.com/numberphile
Brady's videos subreddit: http://www.reddit.com/r/BradyHaran/
Brady's latest videos across all channels: http://www.bradyharanblog.com/
Sign up for (occasional) emails: http://eepurl.com/YdjL9