Imaginary Numbers are Matrices [Japanese with English captions] – If you would like to have imaginary numbers and quaternions explained in the form of a dialogue between anthropomorphized vocal synthesizers, then Zundamon and Metan are here to oblige you. Zundamon's Theorem is a channel with more of these mathematically enriching conversations.

What it says on the tin. (Gift link, New York Times) Come for the cooking technique; stay for the radius, standard deviation, and not-actually-surprising ending. Previously on Metafilter: J. Kenji Lopez-Alt; onions.