From Snopes https://www.snopes.com/fact-check/machine-automatically-sorting-colored-balls/

from the yt description:

A Galton board, also known as a bean machine, quincunx or Galton box, was developed by Sir Francis Galton in the 1800 to demonstrate the central limit theorem.
In reality, this machine doesn’t exist. This video is a computer simulation of a “Galton board” with Blender, an open-source 3D computer graphics software.
Firstly, simulation was run with all white balls. When the objects all settled, they assigned each ball a color and ran the program again.

CG physics very apparent.

boring to learn it's CG.

I had assumed some optical trickery... e.g. the balls are all the same colour but they appear different colours depending on which pit they fall into.

some of the balls towards the end just flat out disappear

I was thinking something more like a controlled liquid viscosity combined with different weighted balls. Sad to see its just a cg render.