用 3.14 分钟讲清 e^(iπ)（用动力学）

A short 3Blue1Brown video explaining Euler's formula e^(i*pi) = -1 through dynamics, treating velocity as the thing that moves a point to a new position. It builds geometric intuition for why an exponent with i produces rotation.

Why HN likes it: HN commenters point to it as a quick, visual way to understand Euler's identity.

“3blue1brown explains it better than I could”