Imagine being presented with two envelopes. One envelope contains twice as much money as the other, and you are allowed to look inside an envelope before deciding whether to switch or not. This problem is known as the exchange paradox. This Demonstration simulates the effectiveness of two different strategies: the red data points represent the strategy of switching to the other envelope, and the blue data points represent keeping the original envelope. The axis is the cumulative amount of money, and the axis is the number of trials.