A mathematical YouTube channel begun by Grant Sanderson in 2015 that addresses a wide range of mathematical topics using animated videos. In the videos there are animated pi-shaped characters, a tutor who is brown, and three students who are blue, though the name originally comes from the heterochromia in Grant’s right eye.

https://www.youtube.com/channel/UCYO_jab_esuFRV4b17AJtAw The 3blue1brown YouTube channel.

https://www.3blue1brown.com/ The official 3blue1brown website.