Build a jar of winning (green) and losing (red) marbles, pull from it, and watch how your results converge toward the jar's expected value over many draws. Every draw is independent and the marble goes back in — exactly like the jar in the article.
1 · Build your jar
60
40
Win (green)
Lose (red)
Expected value / draw
+$0.20
Win chance
60%
Positive expected value — the jar tilts in your favor.
2 · Pull marbles by hand
—
$0.00
0 draws · feel the variance of a small number of draws