Plinko

This simulation models a Plinko board, which nicely demonstrates the Central Limit Theorem. At every peg, a falling ball effectively flips a coin to decide whether to bounce left or right.

The bell curve emerges because of path combinatorics. There are far more ways for a ball to reach the center bins than the edges, ending up on the far side requires a rare "perfect streak" of turns in a single direction. In contrast, landing in the center can happen through many different left-right combinations.

This random process naturally results in a Gaussian distribution. You can use the Skew slider to rig the coin flip, shifting the probability to see how bias affects the final expected outcome of the distribution.