From 3Blue1Brown.
A link to the full video answering this is at the bottom of the screen. Or, for reference: https://youtu.be/LqbZpur38nw
Thanks to these viewers for their contributions to translations
Bulgarian: Martin Grozdanov
French: GiveMeChocolate, Yoyodotpy
German: Josh, dlatikay
Hebrew: Omer Tuchfeld
Hindi: rajeshwar-pandey
Spanish: Marcelo Lynch