IMHO: Of all of the videos showing Pi's relationship with the Arithmetic-Geometric Mean (AGM), this is the best one.

Related:

Gauss–Legendre algorithm:

https://en.wikipedia.org/wiki/Gauss%E2%80%93Legendre_algorit...

Arithmetic–Geometric Mean (AGM)

https://en.wikipedia.org/wiki/Arithmetic%E2%80%93geometric_m...

Chudnovsky algorithm

https://en.wikipedia.org/wiki/Chudnovsky_algorithm

Landen's transformation

https://en.wikipedia.org/wiki/Landen%27s_transformation

Binary splitting:

https://en.wikipedia.org/wiki/Binary_splitting