A pegboard device puts normal distribution on display. You drop 200 marbles through a grid of wooden dowels that deflect each marble randomly left or right. About 50% land in the two center slots, while only 16% reach the two outermost slots on each end. Each random bounce adds up across many rows, and the combined effect pushes most marbles toward the middle. The pattern repeats within 5% on every trial — and the results form a bell curve, the defining shape of a normal distribution.