Galton board

The Galton board, also known as the Galton box or quincunx or bean machine (or incorrectly Dalton board), is a device invented by Francis Galton to demonstrate the central limit theorem, in particular that with sufficient sample size the binomial distribution approximates a normal distribution.

Galton designed it to illustrate his idea of regression to the mean, which he called "reversion to mediocrity" and made part of his eugenist ideology.