From the 60's to the 80's, Monty Hall hosted the gameshow “Let's Make a Deal.” Contestents opened doors to win money, furniture, cars... or, hilariously, just farm animals.

The concept was borrowed for a controversial statistical puzzle, although Monty Hall insists "Let's Make a Deal" never had an event with this puzzle's interesting kink. Monty Hall presents three doors, one concealing a car, the other two concealing goats. (You want the car.) After you pick a door (say, door 1) Monty Hall opens a different door (say, door 2) to show a goat. Then Monty Hall asks if you want to stay with your choice of door (door 1) or swap to the remaining door (door 3).

The intuitive answer is that the choice shouldn’t matter. With two doors, one car, and one goat, there should be a 50% chance of winning the car whether we swap or stay. However, this is not the case! Because there was a ⅔ chance the first choice of door conceals a goat, there is a ⅔ chance the remaining door conceals the car.

This program presents this gameshow with PyGame. Click on doors to find goats or cars.