The Bean Machine

Drop balls through a wall of pegs — pure coin-flip randomness — and watch a perfect bell curve build itself.

Show the predicted curve Peg rows

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balls

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avg bin

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spread

What am I looking at?

Each ball hits a peg and bounces left or right with a 50/50 chance — like flipping a coin at every row.
The coral bars count how many balls landed in each bin. They grow live as balls land.
The green dashed line is the mathematical prediction (the "bell curve"). No ball knows about it — yet they obey it.
Avg bin and spread compare your live results against theory (shown in grey). More balls → closer match.

The takeaway

Add up many small random events and the result is predictably bell-shaped — this is the Central Limit Theorem in action, no equations needed.
It's why heights, measurement errors, and exam scores so often look like bells: each is the sum of many tiny coin flips.