A Galton Board (or Bean Machine) consists of a vertical board with a triangular array of pegs. Balls dropped from the top bounce hitting pegs, moving left or right with equal probability.
Combinatorics: The number of paths to the $k$-th bin in row $n$ is the binomial
coefficient $\binom{n}{k}$.
Probability: For large $n$, this approximates the Normal Distribution.
Instructions: Drop balls to see the distribution form. Speed up the simulation with the slider.