• Math
• mathematics
• topology
• inscribed square problem
• 3b1b
• 3 blue 1 brown
• three blue one brown

An unsolved conjecture and a clever topological solution to a weaker version of the question that shows how the torus and mobius strip naturally arise in mathematical ponderings.

Thanks to everyone supporting at https://www.patreon.com/3blue1brown, and thanks to https://www.hover.com/, where you can get 10% off using the promo code TOPOLOGY.

Proof due to H. Vaughan (1977).

Special shout out to the following patrons: Juan Batiz-Benet, Loo Yu Jun, Tom, Othman Alikhan, Markus Persson, Joseph John Cox, Achille Brighton, Kirk Werklund, Luc Ritchie, Ripta Pasay, PatrickJMT , Felipe Diniz, Chris, Andrew Mcnab, Matt Parlmer, Naoki Orai, Dan Davison, Jose Oscar Mur-Miranda, Aidan Boneham, Brent Kennedy, Henry Reich, Sean Bibby, Paul Constantine, Justin Clark, Mohannad Elhamod, Denis, Ben Granger, Ali Yahya, Jeffrey Herman, and Jacob Young